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1. e Centre 1 A un wa ec o oc J Centre 2 Lu oO dSNRN 1 mGy de Normalized from 10 to 1 mGy N o IB eo 0 50 100 150 200 250 kV FIG 30 BAM measured centre efficiency at different radiation energies Data in Fig 30 were taken with 2 s frame time and 2 frames centre 1 and with 0 2 s and 20 frames centre 2 for exposure with 1 mGy A third exposure was taken with 2 s frame time and 20 frames with a total exposure of 10 mGy This curve was normalized by l sqrt 10 and included in this figure The developed fluoroscope has the highest sensitivity at about 100 kV tube voltage At lower energies the protecting input screen of 1 mm AI limits the efficiency and at higher energies the efficiency declines because of the reduced attenuation of the fluorescence screen 4 3 MEASUREMENTS OF ACHIEVABLE CONTRAST SENSITIVITY AND SPECIFIC MATERIAL THICKNESS RANGE These measurements according to Section 3 3 3 and ASTM E 2597 allow the contrast sensitivity of the digital fluoroscope to be evaluated depending on the material and its wall thickness For aluminium a wall thickness of up to 100 mm was investigated for steel up to 12 5 mm The radiation quality 1s fixed to 160 kV and 0 5 mm Cu at the tube port in accordance with ASTM E 2597 Tables 9 and 10 give measurement results for aluminium and steel step wedges with six steps TABLE 9 MEASUREMENT RESULTS FOR ACHIEVABLE CONTRAST S
2. 45 Therefore the detector shows the wire 19 indication with a sub pixel resolution The DFS investigations also show improved wire visibility even if the wire diameter is smaller than the basic spatial resolution of the DFS rM ye ee i gt j a FIG 36 a Step wedge of steel with ASTM E 1025 IOls for determination of image quality SOkKV ImAmin 2mA min SmAmin 10mAmin 20mA min 0 05 in 2 1 1 1 0 07 in 2 2 2 1 0 10 in 2 2 2 1 0 12 in 4 2 2 1 0 15 in 2 2 2 0 20 in 9 0 25 in 100KV 1mA min 2mAmin 5mA min m min 0mA min 0 05 in 2 1 1 1 1 0 07 in 2 2 1 1 1 0 10 in 2 2 l 1 1 0 12 in 2 2 1 1 1 0 15 in 4 2 2 1 1 0 20 in 1 2 1l 1 0 25 in 1 1 150kV 1mA min 2mAmin SMmAmin 10mAmin 20m min 0 05 in 2 1 F l ri 0 07 in 2 il 1 7 0 10 in 2 2 1 2 0 12 in 2 3 2 1 0 15 in 2 2 2 1 1 0 20 in 4 2 2 l 1 0 25 in 4 2 2 1 2 FIG 38 b Achieved IQI quality smallest visible hole of 2 IOI I IT hole 2 2T hole 4 4T hole as a function of kV mA min and wall thickness in inches for test object shown in FIG 38 a 46 1 v D gt ie d P v i i b 3 gt REIN highpass filtered Draht EN 462 1 BE a W13 200um EEE d melt W14 160um 100um contrast resolution W15 130um DDA magnification 1 W16 100um W19 50um contrast resolution W17 80um class B W18 63pm 200pm pixel size W19 50um FIG 39 Comparison of visibility of wire
3. 550 0 Gamma White Balance i F Register Read Write Register Address FO000400 Read Register Value 00000000 Write Default View Live View raw v Fit to View v ROI automatic Source Device 0 Y 1388x1040 amp 5 00 fps qv 1 43 Source calibration m OK APER C Apply temporal filter 5 Frame integration Store to FIG 14 Typical image with clipped grey level values as result of incorrect selection of brightness and shutter left and optimum settings of the camera FOculus FO 442SB right 20 On the right hand side of Fig 14 is the camera control Windows shown for the FOculus FO 442SB camera after pressing the Setup button in the V2 main window Only the Net Video Control tab is of importance the NET Camera Control tab should not be changed The other important setting parameter electronic Shutter will set the exposure time for the single camera frame This value is an encrypted value derived from the frame time in ms Depending on the selected frame time the correct Brightness setting will change because the dark signal of the CCD chip will increase with increasing frame exposure time So it is useful to operate the fluoroscope only with a very limited number of different shutter settings because the fluoroscope calibration also depends on this setting Depending on the av
4. 15 l Camera holder part 1 Aluminium alloy 16 l Camera holder part 2 Aluminium alloy 17 18 2 Lead glass holder upper side X5CrNil8 19 l Lead glass holder bottom side X5CrNil8 20 l CCD camera purchased 21 l Lead glass purchased Lead glass Pb glass 22 2 Spring diameter 10 mm x 1 mm x 13 mm purchased XSCrNi18 23 l Inner casing right plate X5CrNil8 24 l Inner casing left plate X5CrNil8 25 l Inner casing left shielding Lead Pb 26 l Inner casing right shielding Lead Pb 27 l Inner casing from main beam shielding Lead Pb 28 l Inner casing top shielding Lead Pb 29 l Inner casing bottom shielding Lead Pb 30 1 Inner casing rear shielding Lead Pb BS 4168 M4 x 10 4 Hexagon socket set screw with cone point X5CrNil8 DIN 7991 M4 x 12 12 Hexagon socket countersunk head screw X5CrNil8 DIN 7991 M4 x 16 12 Hexagon socket countersunk head screw X5CrNil8 DIN 7991 M4 x 20 22 Hexagon socket countersunk head screw X5CrNil8 DIN 7991 M5 x 16 Hexagon socket countersunk XSCrNilg head screw DIN 912 M4 x 20 17 Hexagon socket head cap screw X5CrNil8 DIN 912 M4 x 25 l Hexagon socket head cap screw X5CrNil8 DIN 912 M5 x 16 8 Hexagon socket head cap screw XSCrNi18 DIN 912 M5 x 20 12 Hexagon socket head cap screw XSCrNi18 TABLE 2 TRANSLATION OF TERMS IN THE DRAWINGS German English Teil Bauteil part Gehause Kameragehause Detektorgehause Casing camera casing fluoroscope casing Kameraabschirmung Camera shielding
5. The intrinsic photon detection in photodiodes works fine for light photons and X ray photons up to 20 keV Above that level the absorption rate caused by the thin photodiode layer is too low for effective image generation For higher X ray energies indirect detection is used based on a scintillation screen as used in a fluoroscope but here it is in direct contact with the photodiode matrix for light detection In this way nearly all light photons leaving the scintillator screen are collected by the photodiodes directly touching the screen All losses connected with light imaging by a mirror and lens as used in fluoroscopes are omitted The photodiode layer should not be degraded by X ray radiation and the light detection should not be degraded by the penetrating X ray photons Because CCD elements are very sensitive to X rays and cannot be used in direct contact with the scintillator photodiodes made on complementary metal oxide semiconductor CMOS or amorphous silicon panels are used for light detection In what is commonly called an amorphous silicon flat panel X rays or gamma rays first strike a scintillation layer This layer emits photons in the visible spectrum These photons are picked up by the underlying amorphous silicon photodiode array which converts them to an electric charge This charge is then converted into digital values for each pixel The scintillation layer is commonly composed of either caesium iodide or gadolinium oxysul
6. 10 3 2005 EU project Film Free http www filmfree eu com 200 2009 EUROPEAN COMMITTEE FOR STANDARDIZATION CEN EN 14874 NDT industrial computed radiography with storage phosphor imaging plates CEN EUROPEAN COMMITTEE FOR STANDARDIZATION EN 444 1994 Non destructive testing General principles for radiographic examination of metallic materials by X and gamma rays CEN 2004 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 462 1 1994 Non destructive testing Image quality of radiographs Part 1 Image quality indicators wire type Determination of image quality value CEN 1994 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 462 2 1994 Non destructive testing Image quality of radiographs Part 2 Image quality indicators step hole type Determination of image quality value CEN 1994 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 462 5 1996 Non destructive testing Image quality of radiographs Part 5 Image quality indicators duplex wire type determination of image unsharpness value CEN 1996 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 462 3 1997 Non destructive testing Image quality of radiographs Part 3 Image quality classes for ferrous metals CEN 1997 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 1435 1997 Non destructive examination of welds Radiographic examination of welded joints CEN 1997 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 13068 3 2001 Non destructive testing Radioscopic t
7. 34 91 781 94 80 Fax 34 91 575 55 63 Email compras diazdesantos es carmela diazdesantos es barcelona diazdesantos es jullo diazdesantos es Web site http www diazdesantos es UNITED KINGDOM The Stationery Office Ltd International Sales Agency PO Box 29 Norwich NR3 1 GN Telephone orders 44 870 600 5552 enquiries 44 207 873 8372 Fax 44 207 873 8203 Email orders book orders tso co uk enquiries book enquiries Qtso co uk Web site http www tso co uk On line orders DELTA Int Book Wholesalers Ltd 39 Alexandra Road Addlestone Surrey KT15 2PQ Email info profbooks com Web site http www profbooks com Books on the Environment Earthprint Ltd PO Box 119 Stevenage SG1 4TP Telephone 44 1438748111 Fax 44 1438748844 Email orders earthprint com Web site http www earthprint com UNITED NATIONS Dept 1004 Room DC2 0853 First Avenue at 46th Street New York N Y 10017 USA UN Telephone 800 253 9646 or 212 963 8302 Fax 212 963 3489 Email publications un org Web site http www un org UNITED STATES OF AMERICA Bernan Associates 4501 Forbes Blvd Suite 200 Lanham MD 20706 4346 Telephone 1 800 865 3457 Fax 1 800 865 3450 Email customercare bernan com Web site http www bernan com Renouf Publishing Company Ltd 812 Proctor Ave Ogdensburg NY 13669 Telephone 888 551 7470 toll free e Fax 888 568 8546 toll free Email order dept renoufbooks com Web sit
8. PALAU PANAMA PAPUA NEW GUINEA PARAGUAY PERU PHILIPPINES POLAND PORTUGAL QATAR REPUBLIC OF MOLDOVA ROMANIA RUSSIAN FEDERATION RWANDA SAUDI ARABIA SENEGAL SERBIA SEYCHELLES SIERRA LEONE SINGAPORE SLOVAKIA SLOVENIA SOUTH AFRICA SPAIN SRI LANKA SUDAN SWAZILAND SWEDEN SWITZERLAND SYRIAN ARAB REPUBLIC TAJIKISTAN THAILAND THE FORMER YUGOSLAV REPUBLIC OF MACEDONIA TOGO TRINIDAD AND TOBAGO TUNISIA TURKEY UGANDA UKRAINE UNITED ARAB EMIRATES UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND UNITED REPUBLIC OF TANZANIA UNITED STATES OF AMERICA URUGUAY UZBEKISTAN VENEZUELA VIETNAM YEMEN ZAMBIA ZIMBABWE The Agency s Statute was approved on 23 October 1956 by the Conference on the Statute of the IAEA held at United Nations Headquarters New York it entered into force on 29 July 1957 The Headquarters of the Agency are situated in Vienna Its principal objective is to accelerate and enlarge the contribution of atomic energy to peace health and prosperity throughout the world IAEA RADIATION TECHNOLOGY REPORT No 2 DESIGN DEVELOPMENT AND OPTIMIZATION OF A LOW COST SYSTEM FOR DIGITAL INDUSTRIAL RADIOLOGY INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA 2013 COPYRIGHT NOTICE All IAEA scientific and technical publications are protected by the terms of the Universal Copyright Convention as adopted in 1952 Berne and as revised in 1972 Paris The copyright has si
9. Spiegel Mirror first surface mirror Halter Holder Bolzen Bolts Platte Plate Blech Thin plate thin metal sheet Blei Lead Pb For details see the drawings in the Annex to this publication 2 20 SELECTION OF MATERIALS AND COMPONENTS FOR CONSTRUCTION OF A DIGITAL FLUOROSCOPE In addition to the drawings used to construct the housing including X ray and light shielding some components have to be purchased commercially The drawings are adapted to the selection of special parts as described in the following If other parts are used some of the construction details may need to be changed To assemble a digital fluoroscope the items listed in Table 3 need to be purchased one item per position The total price of the components for one fluoroscope unit excluding personal computer and FireWire hub was about 2160 excluding value added tax in Europe in 2008 2 3 INSTRUCTIONS FOR ASSEMBLY OF DIGITAL FLUOROSCOPE HOUSING The manufactured digital fluoroscope housing and shielding components comprise 26 fabricated details two springs detail No 22 a CCD camera with an objective a first surface mirror a fluorescent screen lead protecting glass and number of connecting screws Fig 4 Detail numbers mentioned in this section correspond to those in the BAM drawings provided in the Annex to this publication FIG 4 The fluoroscope housing and shielding details to be assembled 10 For the assembling processes 1 The hous
10. Telephone 358 9 121 41 Fax 358 9 121 4450 Email akatilaus akateeminen com Web site http www akateeminen com FRANCE Form Edit 5 rue Janssen P O Box 25 F 75921 Paris Cedex 19 Telephone 33 1 42 01 49 49 Fax 33 1 42 01 90 90 Email formedit formedit fr e Web site http www formedit fr Lavoisier SAS 145 rue de Provigny 94236 Cachan Cedex Telephone 33 1 47 40 67 02 Fax 33 1 47 40 67 02 Email romuald verrier lavoisier fr e Web site http www lavoisier fr GERMANY UNO Verlag Vertriebs und Verlags GmbH Am Hofgarten 10 D 53113 Bonn Telephone 49 228 94 90 20 Fax 49 228 94 90 20 or 49 228 94 90 222 Email bestellung uno verlag de Web site http Awww uno verlag de HUNGARY Librotrade Ltd Book Import P O Box 126 H 1656 Budapest Telephone 36 1 257 7777 Fax 36 1 257 7472 Email books librotrade hu INDIA Allied Publishers Group 1st Floor Dubash House 15 J N Heredia Marg Ballard Estate Mumbai 400 001 Telephone 91 22 22617926 27 Fax 91 22 22617928 Email alliedpl gvsnl com Web site http www alliedpublishers com Bookwell 2 72 Nirankari Colony Delhi 110009 Telephone 91 11 23268786 91 11 23257264 Fax 91 11 23281315 Email bookwell vsnl net ITALY Libreria Scientifica Dott Lucio di Biasio AEIOU Via Coronelli 6 I 20146 Milan Telephone 39 02 48 95 45 52 or 48 95 45 62 Fax 39 02 48 95 45 48 Email info libreriaaeiou eu Website www libreriaaeiou
11. o D D S 0 O Specimen Reference block Material Stainless Steel JdOISOUONI4 Iv LIOIG N3lNIO3dS JO HdVHDOLOHd 50 Catalogue Test Sample IAEA 001 Specimen Casting Welding Process Joint Preparation Material Carbon Steel Nominal Thickness 15 mm Source X Ray DIGITIZED FILM ARG FL FE C 15 10 160KV 18mA 400mm 460s o e N E E e gt SY I CL 9 18 2 Xx O S 35 yj LS e i lt Lo E y Xd C mu LLI LL a LL D Y PHOTOGRAPH OF SPECIMEN ARG IN FE C 15 10 110KV 12mA 700mm 32s Discontinuities Porosity category A shrinkage sponge cracks 5 Catalogue Test Sample IAEA 002 Specimen Casting Welding Process Joint Preparation Material Aluminum Nominal Thickness 20mm Source X Ray 7 sy t ues n oan s DEL EUR SOC ETC Fi il DIGITIZED FILM ARG FD AL C 20 04 60KV 10mA 700mm 160s DIGITAL FLUOROSCOPE ARG AL C 20 04 gt TI X Mr m Q LL op D LL z S T a z LU g a O T Q Discontinuities Foreign Material shrinkage sponge 52 ARG FL AL C 20 04 90KV 32mA 700mm 3608 ARG IN AL C 20 04 50KV 15mA 700mm 32s co D I c Li lt o Q G u D 2 D o f O gt n D S 0 c je w w i m A E O 9 lt L H v 0 Q O O i LL D S 9 9 E D E O m Q N Ray Source X Nominal Thickness 12 7 mm Materi
12. 00 X 90 EN 24 20 DURCH DIN 74 58 00 X 90 120 00 Camera shielding part 27 material Lead I C Qc 2 ce e ce co Q All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 Camera shielding part 28 material Lead 0 70 1 20 00 All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 Camera shielding part 29 material Lead Camera shielding part 30 material Lead 89 Azizova A Dorobantu V Ewert U Garci A Hamzah A R Harara W Infanzon S Jin Joon Ha Khan A A Rao B P C Venkatraman B Zaheer A Zscherpel U CONTRIBUTORS TO DRAFTING AND REVIEW Navoi Mining and Metallurgy Combinate Uzbekistan Timisoara Politechnica University Romania Federal Institute for Materials Research and Testing Germany National Atomic Energy Commission Argentina Ministry of Science Technology and Innovation Malaysia Atomic Energy Commission Syrian Arab Republic Uruguayan Society for NDT AENDUR ANCAP Uruguay International Atomic Energy Agency International Atomic Energy Agency International Atomic Energy Agency Indira Gandhi Centre for Atomic Research India National Centre for Non Destructive Testing Pakistan Federal Institute for Materials Resear
13. 09 07 56 12 08 46 21 14 Pakistan 4 03 02 02 04 03 02 11 07 06 13 I 1 19 15 LS 24 17 16 Romania L8 33 32 23 22 18 14 29 2 1715 7 36 32 86 44 45 12 73 72 Syrian Arab Republic 4 15 09 05 15 09 05 15 08 05 16 11 06123 15 08 31 22 14 Uruguay 8 12 06 04 I 06 03 12 06 04 14 07 05 26 I 09 38 16 13 Uzbekistan 45 21 21 21 14 14 14 25 L6 1 24 15 11 52 41 34 13 73 65 The specific contrast CSa as reported in Tables 9 and 10 increases with the exposure time but decreases for a fixed exposure condition with increasing wall thickness Finally the achieved SMTR was reported by the different countries as presented in Table 11 TABLE 11 SNR VALUES FOR EACH STEP OF THE ABOVE STEP WEDGES AND THE RESULTING SPECIFIC MATERIAL THICKNESS RANGE SMTR mm FOR SNR gt 130 or SNR gt 250 SNR at Step DES med a E Sf re fo pslis ps 256 16 pe 256 16 e 256 16 16 256 16 16 Jass 10 er pre 16 ss 236 m Lr spass sers s RT nope ep np vp sp np sp spun sw ep EE Steel 12 3 183 272 322 147 245 313 127 208 321 84 135 196 54 100 137 41 72 108 48 75 105 0 25 65 KAM ss enn es sr rp oa me cn rao a a s s reise ao me Sal a ui Steel 2 582 641 701 415 526 612 380 476 545 231 315 446 137 191 276 115 163 207 9 7 12 12 73 amp 8 11 E E de T E dE qp qr ou dr dq Low 4d d ox 13 qd 3 d d D p A 4 132 148 170 109 95 104 49 40 43 32 19 19 24 16 16 17 11 11 10 10 10 Pakistan S
14. 3 D cone beam CT in particular needs computer clusters for image reconstruction of data sets of gigabytes per inspected volume 1 2 7 Advantages of digital radiographic systems Digital industrial radiography DIR has the following benefits It reduces radiation dosage and exposures resulting in less risk to the operator and less disruption to other operations It reduces radiographic inspection time and improves productivity It eliminates film processing chemicals chemical disposal and storage costs Digital radiographs are not degradable It is easily customized for field radiography in a portable package It allows analysis using image processing and defect detection algorithms Storage costs are minimized as all images are stored on hard disks or optical media such as CD ROMs or DVD RAMSs Images can also be accessed via network and even emailed to experts for real time verification Reusable imaging plates mean that savings can be generated as one plate can be used many times Significant cost savings from the use of DIR systems have been reported by industry With the advancement of image intensifier systems imaging plates flat panel detectors and fast multimedia computers DIR is finding increased applications 1 3 ESSENTIAL CONCEPTS RELATED TO DIGITAL INDUSTRIAL RADIOGRAPHY 1 3 1 Radiation attenuation in materials Suppose we have a primary X ray intensity I incident on the surface of a m
15. AND IMAGE CALIBRATION PROCEDURE 3 2 1 Software and hardware installation The selected FireWire camera FOculus FO442SB requires special drivers to operate under Windows operating systems The manufacturer NET GmbH Germany provides the latest version on its web site http www net gmbh com The following files were available during the CRP for download concerning the FO442SB camera 1 FOcontrol Install 4 0 3 0 exe the camera drivers and the demo application FOcontrol exe 2 FOcontrol V3 0 7 0 manual pdf the user manual for the demo application FOcontrol exe 3 NET FOculus S user manual v1 15 OQ01 pdf the detailed description of the FO442SB camera specifications and the software and driver installation The first file has to be started once on the computer to install all necessary drivers and the demonstration application FOcontrol exe Finally a link to this demonstration application is installed on the desktop After the software installation reconnect the camera to the hot pluggable FireWire interface Only then will all necessary Windows drivers be installed and the camera become visible under the system gt hardware gt device manager as image processing device with the name NET GmbH 1394 Digital Camera When the device is shown in the manager window without a yellow exclamation mark the camera is ready for operation A beep should be heard from the computer when the camera is connected or disconnected on
16. ASTM E 2597 standard for digital fluoroscope qualification For full information and understanding of the concepts it is necessary to read the full standard text of ASTM E 2597 Oo Maga ta g El ba N 92 Sd CAT A B4x 967 500 GW 33083 SNR 15 meet tal Zo Vil VO SI ATA u kan E Saos St el FIG 17 Images of an Inconel step wedge with ASTM 2 2T penetrometers after digital high pass filtering Enhance details Top image without calibration only 2 4T holes are visible Bottom after application of fluoroscope calibration to the raw data Vertical banding is removed the steps are more homogeneous and 2 2T holes are visible between 0 2 5 mm and 0 5 12 5 mm inch thickness Bd 956 26 GW 23411 The following equipment was used for the qualification example X ray equipment YXLON MCF 160 constant potential focal spot of 5 5 mm 160 KV 0 540 mA depending on the voltage Duplex Wire IQI EN 462 5 ASTM E 2002 Aluminium Al and stainless steel SSt step wedges point 5 2 in ASTM E 2597 07 Dose rate meter and video camera to register the values remotely Filters 20 mm AI 38 mm AI and 4 mm SSt used at tube port 25 3 3 1 1 Measurement procedure for basic spatial resolution SR Place the duplex wire IQI directly on the detector fluoroscope with an angle between 2 and 5 to the rows columns of the detector to avoid that wire pairs are in th
17. BAM to measure the normalized SNRn of imaging plate scanner systems at 220 kV A DDA was also evaluated for comparison Figure 31 shows the efficiencies of different digital systems in comparison with those of selected digitized X ray films Differential dSNRn values can be measured for the digital fluoroscope and DDAs only because only these can be calibrated Differential comparison cannot be applied accurately with other CR systems Therefore the uncalibrated SNRn values were compared Comparison of Efficiency of Different Digital Detectors oc ag I E ld o 360 E 310 260 210 UO 160 a x 110 a ag Loy E 2l B SNRN 10 mGy o E un SNRN 1 mGy a ASNRN 3 6 mG S SDS SO y gt amp N X gt S S ge S Q o gt i 9 S S S x amp c AS fon A S A o S Q e JS Q gt Rv ov n n QS o ap NS o I M s amp s Q SS Q amp iv Q Q Q j gt e S Q o 9 S S E QV SS a bo KD Q ge KD e e eS eS FIG 31 Comparison of dSNRn and SNRn values obtained with CR systems of different detectors and films It can be concluded that the DFS has a sensitivity comparable to that of C5 film systems ISO 11699 2 and high resolution CR systems The advantage of the DFS is its applicability to a wide variety of inspections with different required sensitivities Basically the operator has to decide which dose is required for the exposure 36 Exp
18. R E Digital Image Processing 2nd edn Prentice Hall New Jersey 2002 HAMMAR L WIRDELIUS H Radiographic sensitivity improved by optimized high resolution X ray detector design Int Symp on Digital Industrial Radiology and Computed Tomography Lyon France 2007 HANKE R et al Automated high speed volume computed tomography for inline quality control 16th World Conference on Nondestructive Testing International Committee and Canadian Society of NDT Montreal Canada 2004 HARARA W Digital radiography in industry 17th World Conference on Nondestructive Testing Shanghai China 2008 HARBICH K W HENTSCHEL M P SCHORS J X ray refraction characterisation of non metallic materials NDT amp E International 34 2001 297 302 HEIDT H GOEBBELS J REIMERS P KETTSCHAU A Development and application of a universal CAT scanner Proc 11th World Conference on NDT Las Vegas 1985 664 671 HENTSCHEL M P et al New development in X Ray Topography of advanced non metallic materials 15th World Conference on Nondestructive Testing Rome 2000 http www ndt net article wecndt00 papers idn258 1dn258 htm 63 HOUNSFIELD G N A Method and Apparatus for Examination of a Body by Radiation such as X or Gamma Radiation Patent Specification 1283915 The Patent Office London 1972 INSIGHT Special Edition on Rail Inspection 44 6 2002 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION I
19. Target 140 x 106 mm Versior fr camo ALt my Rak pirt mand sit rre eom de FIG 7 Adjustment of mirror and objective positions in visible light The assembled fluoroscope and the fluorescent screen can be seen in Fig 8 The overall dimensions of the assembly are 285 mm x 195 mm x 182 mm and its approximate weight is 30 kg FIG 8 Assembled fluoroscope and fluorescent screen 13 2 4 PROBLEMS ENCOUNTERED DURING IMPLEMENTATION AND THEIR SOLUTIONS Table 4 shows some of the problems observed during the case studies in participating laboratories as well as their solutions TABLE 4 PROBLEMS ENCOUNTERED AND THEIR SOLUTIONS Problem encountered Light reflection from the internal walls of the housing causes image artefacts Increased background noise due to scattered radiation Dark image distortion no image for thick specimens Unstable image from self rectifying single tank X ray tubes Image distortion caused by improper geometry of the housing smaller or large dimensions of the fluoroscope s optical system Image quality cannot be measured correctly e g Duplex Wire IQI readout or wire number readout is too low Duplex Wire IQI procurement V2 exe software does not work on some computers at all On others it can only run in an unstable way caused by a failing connection of V2 to the direct show library and resulting in no image data and a frame rate of 0 frames per second FO control does not
20. categories of publications the IAEA Radiation Technology Series and the IAEA Radiation Technology Reports IAEA RADIATION TECHNOLOGY SERIES Publications in this category present guidance information or methodologies and analyses of long term validity for example protocols guidelines codes standards quality assurance manuals best practices and high level technological and educational material IAEA RADIATION TECHNOLOGY REPORTS In this category publications complement information published in the IAEA Radiation Technology Series in the areas of radiation processing of materials using ionizing radiation and industrial applications of radiotracers sealed sources and NDT These publications include reports on current issues and activities such as technical meetings the results of IAEA coordinated research projects interim reports on IAEA projects and educational material compiled for IAEA training courses dealing with radioisotope and radiopharmaceutical related subjects In some cases these reports may provide supporting material relating to publications issued in the IAEA Radiation Technology Series All of these publications can be downloaded cost free from the IAEA web site http www iaea org Publications index html Further information is available from Marketing and Sales Unit International Atomic Energy Agency Vienna International Centre PO Box 100 1400 Vienna Austria Readers are invited to provide feedback to th
21. cover the complete step wedge Setup for this measurement should be set to 160 kV with a 0 5 mm Cu filter placed directly in front of the tube The X ray tube current mA under this beam spectrum needs to be determined such that the detector 1s not saturated under the thinnest step for the integration time selected for all tests Images are to be generated by averaging frames to obtain as a minimum 16 64 and 256 s effective exposure times These times should be calculated by multiplying the number of frames by the time of one frame as set by the shutter value in the camera set up of V2 exe The images should be calibrated for this test The signal mean grey value and noise standard deviation of each step should be computed in three rectangular regions as shown in Figs 26 and 27 The minimum size of the rectangular ROI for evaluation is 20 pixels x 55 pixels The noise should be computed in the same rectangular region using the median of the single line standard deviations as listed in ASTM E 2446 and used in ISee CNR 596 should be computed as the ratio of the contrast difference in signal between the region on the groove and those off the groove to the noise of those regions off the groove using Eq 15 as follows CNR 5 0 5 x signal Ca rn 3 signal area 2 15 0 5 x noise area 1 noise area 3 This is computed for each step of the step wedge images With a groove thickness of 5 of the base step
22. dSNRn at 1 mGy dose depending on the radiation quality 1300 M E dSNR f Sqrt Dose mGy d P ond st RV 3cu BHJ 1100 vL v130404 980 4 1000 rE TE 900 P C EN 1 wisn 654 uu 1200 800 is rd N 600 M v 400 LA QE 300 j p gt E 200 FP m 100 A e a 9 a 0 0 0 0 2 0 4 0 6 0 8 1 0 1 2 14 1 6 1 8 2 0 FIG 24 Plot of dSNRn for efficiency measurements at different radiation qualities from ASTM E 2597 28 800 00 700 00 600 00 500 00 c e 60kV c 2 400 00 90kV 20mm Al ov t 120kV 38mm A 300 00 135kV 4m Fe 200 00 100 00 0 00 0 00 0 20 0 40 0 60 0 80 1 00 Sart Dose sqrt mGy FIG 25 Plot of dSNRn for efficiency measurements with the fluoroscope 3 3 3 Measurement procedure for achievable contrast sensitivity and specific material thickness range 1 2 3 4 5 6 7 8 9 10 11 These measurements will be made using the two step wedge test blocks Al and SSt Place the step wedge for all these tests in front of the detector with a source to detector distance of 1000 mm Collimate the beam to an area where only the step wedge is exposed If the area of the detector 1s too small to capture the complete step wedge in one image two or more images with identical X ray and detector settings may be captured to
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24. for all digital fluoroscope settings used during acquisition of exposures a corresponding offset image without any exposure dose is available It is important too that for all measurements done for dSNRn only the raw data of the digital fluoroscope without calibration are used For an example of a correct offset image see Fig 19 File View Image Mode Misc S E amp amp M SLT BVO SIAL 111 I Taken dark image without radiation Stripes indicate that no calibration has been used this is correct and correct brightness and shutter IC EE en has been selected 260 352 486 Statistic window is taken for different positions ip esa me Use value mean 360 6 here exa S fr temples in wander 1176 SAT una devendeey n EN MARE redis sigle bre men 50 9 FIG 19 Acquisition of a correct offset image with the digital fluoroscope The beam current and or time of exposure needs to be adjusted such that a certain known dose rate is obtained at the location of the digital fluoroscope as measured with an ionization gauge dose rate meter Such a dose measurement may be made without any interference from scatter so it is best to complete this measurement prior to placing the digital fluoroscope The dose is obtained by multiplying the dose rate by the exposure time in seconds or fractions thereof To arrive at the 1 mGy dose it is recommended to measure all of the data points a few points below and above the I mGy d
25. images The basic functions of V2 are as follows 1 2 3 4 5 6 7 18 Display of live video in the main window with markers on information clipping grey values of 0 are displayed in blue grey values of 255 in red see Fig 11 Control of camera settings via Setup button Integration of multiple fames to 16 bit greyscale images by averaging of 8 bit frames and scaling to 16 bits for increased dynamic range and SNR Temporal median filtering prior to averaging for suppression of directly converted X ray photons reaching the CCD chip despite the lead shielding Selection of file name for storage of integrated images as standard 16 bit TIFF image Calibration of the integrated raw images via calibration set up file see Section 3 2 3 for reduction of electronic background so called dark image and inhomogeneities between single pixels via additional multiple gain images bright images with flat field X ray exposure of different intensities V2 allows also replacement of bad pixels The calibration procedure file and functionality are the same as used in ISee via the menu Image gt Adjust pixels a About V2 frame averager 2 is a software For acquisition of still images by means of real time Frame averaging of a frame stream e g video stream Additionally it is able to perform pixel correction spatial and temporal and Finally the result can be saved as a standard 16 bit grey leve
26. is selected when a red rectangle is drawn by the mouse left mouse button pressed inside the main image window Then only the grey values inside this red rectangle are considered for automatic histogram scaling to full 8 bit of the display By pressing the right mouse button and moving the mouse the position of this red region of interest ROI rectangle can be moved inside the image window The other settings shown in Fig 13 bottom image from 16 bpp full dynamic up to 4 bits dynamic fix the look up table for image display to the indicated number of bits considered in the image grey values The image at the top of the figure shows the selection of different data streams That in the middle shows the image display with different zooming factors also adjustable via the scroll wheel on the mouse At the bottom are different settings for grey value stretching The numbers on the right hand side show the grey value range displayed between black and white The Reset button in the V2 window resets the used IO library the Setup button calls the camera configuration window The layout of the set up window depends on the camera functionality and the implemented features of the ActiveX video components by the manufacturer of the camera driver For the FOculus camera this is shown in Fig 14 There are only two parameters that have to be adjusted and checked every time the camera is reconnected with the FireWire interface Brightn
27. lens Edmund Optics GmbH Schoenfeldstrasse 185 12 mm 1 1 8 Edmund Optics 8 D 76131 Karlsruhe Germany Product ID NT58 001 Phone 49 0 721 6273730 Fax 49 0 721 6273750 Email infogmbh edmundoptics de Web site http www edmundoptics com 4 First Surface Mirror 81 mm x Edmund Optics GmbH as above 12 100 mm 1 mm support Edmund Optics Product ID Y41 621 5 X ray protective Pb Glas 65 mm Advanced Materials SCHOTT AG 55 x 65 mm 10 mm thickness HuettenstraBe 1 D 31073 Gruenenplan Germany 2 5 mm Pb equivalent 180 kV Phone 49 0 5187 7710 or similar Fax 49 0 5187 771300 Email info gruenenplan schott com Web site www schott com 6 Personal computer running Various brands and models are possible a supplier Not included locally Windows XP and having active FireWire IEEE 1394 interface minimum CPU frequency 2 GHz minimum RAM 512 MB located at the site of the project partner is probably preferable available Active FireWire IEEE 1394 means that the camera power is supplied via FireWire Virtually all six pin connectors found on desktop motherboards have this In laptops notebooks FireWire implementation is usually with a four pin connector these have no power wires In this case an additional active FireWire hub having an external 12V power supply can solve the problem It is also possible to use old external iPod from Apple Inc FireWire adapter cables which enables charging the iPod while conne
28. type IOIs according to EN 462 1 for film left and DDA right at 8 mm wall thickness images high pass filtered for better visualization 4 7 6 Application of compensation principle II If both IQI sensitivities contrast sensitivity by single wires W and spatial resolution by duplex wires D indicated in Table 14 cannot be achieved by the detector system used an increase in single wire visibility is to compensate for too high unsharpness values 1 e if the required D 8 and W 12 are not achieved at the same time for a specific detector set up D 7 and W 13 provide an equivalent detection sensitivity The compensation is to be limited to a maximum compensation of two wires and wire pairs For DDAs the contrast sensitivity depends on the integration time and mA tube current used for acquisition of the radiographic images for a given distance and tube voltage Thus the single wire or step hole visibility can be increased by increasing the frame integration time and or frame number and mA setting This also applies for CR but with limitations associated with the maximum achievable SNR due to the structure noise of the sensitive crystalline photostimulable luminescence layer 4 7 7 Selection of tube voltage The tube voltage for film exposure is to be selected according to curve 2 of Fig 40 for steel and according to curve 4 for aluminium The voltage is not to exceed these values for the radiographic technique For digital radiography it
29. window All possible choices are shown in Fig 13 Live View raw v Fi bo View vi vier automatic O 65535 Live View raw Live View Filtered Source Integration Result uncalibrated gv D 65535 Integration Result Source calibration Ld C Apply temporal filter 5 Frame integration we amp Wien Live View raw w Source calibration C Apply temporal Filter 5 Frame integration Sort m Vien Live View raw v Fit bo View v Viewi automatic v 0 65535 F OT automatic jemw automatic Se 16 bop Full dynamic 14 bits dynamic Source calibration 12 bits dynamic pe amp bits dynamic C Apply temporal Filter 5 Frame integration 6 bits dynamic 10 bits dynamic 4 bits dynamic Source Ox0 0 00 fps gw 0 65535 Store ko Acquire FIG 13 All possibilities to control the image display in the V2 main window 19 The right most bottom menu shown in Fig 13 requires some explanation View automatic is the default greyscale presentation 1 e scaling of the maximum 16 bit grey values in the image data to the 8 bit dynamic range of the display Here the complete image View is automatically scaled 1 e the minimum grey value is scaled to black and the maximum grey value in the image 1s scaled to white The scaled grey value range is displayed on the right most side of the View line The top option ROI automatic
30. wire step hole or plate hole IQIs The image quality values achieved should be the same as or better than those with film radiography 40 Contrast to noise ratio management by increase of radiation dose and the specific DDA or digital fluoroscope calibration allows an extraordinary increase of contrast sensitivity It is obvious that a higher CNR permits the visualization of smaller defects which inherently have a smaller contrast see also Section 1 3 3 The high contrast sensitivity technique has been developed to improve the testing quality and to prove the compensation principles TABLE 13 BASIC STANDARD REQUIREMENTS FOR FILM AND DIGITAL RADIOLOGY IN COMPARISON Film Digital detector CR Achieve minimum SNRn Achi ini tical densit l i chieve minimum optical density or calibrated minimum pixel value Do not exceed maximum unsharpness Correct geometry and detector selection Prove minimum IQI perception with Wires Achieve minimum CNRn Step holes or use same IQIs to prove quality Plate holes use optional unsharpness IQI 4 7 2 Requirements for image quality in digital industrial radiology After qualification of the digital fluoroscope it is to be used with a sufficient frame time and frame integration number for providing digital radiographs with an SNRn 7100 in the heat affected zone of the weld radiographs and SNRn gt 70 in the image region of the thickest section of the casting The measurement of SNRn
31. 1 50 47 50 30 00 4 20 DURCH DIN 74 7 00 X 90 41 50 47 50 30 00 Part 6 material Aluminium All tolerances must be within 0 05 73 74 4 20 DURCH DIN 74 87 00 X 90 Part 7 material V2A All tolerances must be within 0 05 M6x1 6g 212 00 M4x0 7 6H Part 9 2x material V2A All tolerances must be within 0 1 4 20 DURCH DIN 974 58 00 X 4 00 Part 10 material V2A All tolerances must be within 0 1 Mirror and camera holes All tolerances must be within 0 02 75 76 Mirror and camera holder Teil is German for part Mirror holder part 11 material V2A All tolerances must be within 0 02 71 78 F YF Teil 24 Camera shielding and holder Teil is German for part fik dk W JT MENE Teil 14 Teil 19 Camera shielding and holder Teil is German for part FI Teil 20 Teil 17 18 ik 79 M 0 90 1 Teil 28 Teil 29 Teil 30 Camera shielding and holder Teil is German for part dk 80 a F W 090 1 Camera shielding and holder Teil is German for part i ik 81 82 All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 Camera shielding part 13 material V2A 24 50 DURCH 03 50 DURCH Camera shielding part 14 material V2A All tol
32. 20 resolution of the gap 2 R and R are the modulation of the corresponding wire pair dip value of D and D respectively 24 TIT au l I i h I 1 I re mv 0 x an e n 6 10 18 w w m i xo w AD 19 LE 20 in 40 amp diam mt Signal value Wire pair distance Nore Schematic of the measurement is shown at lower right FIG 18 Evaluation of the duplex wire IQI for determination of SR 3 3 2 Measurement procedure for efficiency dSNRn 1 2 3 The efficiency of the digital fluoroscope is measured in the free beam without an object in front of the digital fluoroscope For comparison between participants and between other detectors such as film CR or DDAs a typical dose of 1 mGy at the detector is used The measurement is to be performed at a few points where the dose is above and below 1 mGy The efficiency at 1 mGy can then be computed from the series of measured points The series of points measured during the tests and a linear interpolation function including the point 0 dose 0 dSNRn verifies that the measurements are reliable and without artefacts For simple verification a dose of 1 mGy is reached if a D7 film including 0 025 mm Pb screens shows a density of about 0 6 above fog Obtain an offset image black image without radiation with the digital fluoroscope using the same frame time shutter and brightness setting in V2 as will be used later for the dose exposures It is essential that
33. ENSITIVITY CSa 96 FOR ALUMINIUM STEP WEDGE WITH SIX STEPS 10 20 40 60 80 AND 100 mm THICKNESS SDD 1000 mm SOD 600 mm pre filter 0 5 mm Cu voltage 160 kV CSa 96 at step No Tube 1 2 3 4 5 6 u pum Exp time s Exp time s Exp time s Exp time s Exp time s Exp time s 16 64 256 16 64 256 16 64 256 16 64 256 16 64 256 16 64 256 Argentina 14 05 04 04 03 02 02 03 03 0304 04 03 04 03 03106 0 4 0 3 Germany 3 5 19 I 08 16 I 05 Zl 13 09 1 5 3 5 7 Pakistan 32 02 55103 02 021 09 05 04 17 13 13 2 18 162 5 1 8 1 6 4 Romania 1 16 13 14 15 13 11 19 21 14 2 26 19 21 22 17132 36 3 Syrian Arab Republic 4 1 2 09 0 6109 07 04 12 08 041 18 11 06 29 22 12 5 38 2 8 8 1 1 06 0 3108 04 03 I 05 03 13 07 04 27 14 LI 5 32 25 Uruguay 34 TABLE 10 MEASUREMENT RESULTS FOR ACHIEVABLE CONTRAST SENSITIVITY CSa FOR STAINLESS STEEL STEP WEDGE WITH SIX STEPS 1 3 2 5 5 7 5 10 AND 12 5 mm THICKNESS SDD 1000 mm SOD 600 mm pre filter 0 5 mm Cu voltage 160 kV CSa 96 at step No Tube 1 2 3 4 5 6 un ne Exp time s Exp time s Exp time s Exp time s Exp time s Exp time s 16 64 256 16 64 256 16 64 256 16 64 256 16 64 256 16 64 256 Mn 123 1 06 05 26 16 12104 02 02 04 02 02 06 03 02 06 03 02 India 2 17 1 07J15 1 05 15 13 04 26 14 08 36 32 1155 07 13 Malaysia 8 13 07 04 12 06 03 12 06 04 24
34. ERES qa d ES 1 1 The radiographic testing method egere Son 303 875 br EHE S rate aba ve btw s eee ees 1 2 Filmless radiographic testing Methods u soam 44 54 0 0 ee REM AERE UR ke d d 1 2 1 Limitations of the conventional film RT method 0 000 navne 122 FANN rer ST 125 Fluoroscopy and radioscOpy sene RAT 1 2 4 Computed radiography with imaging plates liliis 1 2 5 Digital detector arrays or flat panel detectors 22e sek e ea 1 2 6 Computed tomography s arsesresamsanek er a ee RR ek Goh eee IRR RR RR RA RR 1 2 7 Advantages of digital radiographic systems 22 6620660 iu us 1 3 Essential concepts related to digital industrial radiography 0 0 0 0 0 1 3 1 Radiation attenuation in Materials zu 2402 0 1 u Be een D X Date Ds OT TIm IMa E 5 pea eee ta Gee as eee ee a ra er SS ES IE 1 3 3 MUNN pre DESIGN AND CONSTRUCTION OF FLUOROSCOPIC SYSTEM FOR DIGITAL INDUSTRIAL RADIOLOGY seg 02H as RE goo qc edda gerat wee hace 2 1 BAM construction drawings for digital HuoOtoscope ueste y aereo ERREUR REO ees 2 2 Selection of materials and components for construction of a digital fluoroscope 2 3 Instructions for assembly of digital fluoroscope housing 0 00 0 ee eee 2 4 Problems encountered during implementation and their solutions 00008 2 5 Cost analysis of various digital industrial radiology systems 00 00 EXPERIMENTAC PROCEDU
35. Fe 130 kV 0 5 m FOD 100 mAs BAM fluoroscope 17 mA 6 sec ST VI IP D rr CR35V 10 mA 10 sec c d FIG 33 Comparison of a DFS und b CR radiography The radiographs were taken under the same exposure conditions After high pass filtering it can clearly be seen that c the DFS image is less noisy and shows better the crack details despite the higher unsharpness than d the CR image 38 4 6 EXPERIENCE WITH ISOTOPIC RADIATION SOURCES A successful attempt was made by India to use the digital fluoroscopic system with gamma rays Ir It is pertinent here to point out that in industrial radiography isotopic sources are widely preferred for field applications and a wide variety of sources such as Se Yb and Ir are in use Experiments using Ir were quite encouraging Images could be obtained with suitable collimation of the radiation beam focused primarily on the ROI and additional shielding around the casing to prevent scattered radiation from reducing the SNR The DFS was used for the examination of welds using Ir The objects chosen were 8 and 10 mm thick stainless steel welds Since these were preliminary trials the choice of the thickness was based on the source activity 18 Ci and the source detector distance which was fixed at 400 mm to ensure a higher dose rate at the detector face A slightly longer integration time was also used Figure 34 a shows the gamma ray image of the weld with the DFS The ra
36. G ISee 1s software developed by BAM for the purpose of radiographic image analysis using the Microsoft Windows operating system The demonstration and full versions of this software along with the user manual can be downloaded from the Internet http www kb bam de ic There is no installation required The entire file can be copied to a personal computer and run using the ic exe or 1c demo exe file as applicable To process images open the digital image in ISee just drop the image file via mouse on the ISee program icon The digital images can be raw data without calibration or can be captured including calibration The image stored in the form of raw data is calibrated by using ISee for optimum contrast sensitivity and better flaw detection with the digital fluoroscope The main purpose is analysis i e adjustment for the human eye of various tasks such as wall thickness measurement profile based measurement calculation of image statistics SNR measurement in a defined window region various types of filter for image enhancement and documentation of high resolution images with high bit depth usually arising in scientific and industrial digital imaging and in DIR in particular The details of functions and parameters for operation are available in the user manual The manual also provides tips on useful image processing tools for better visualization of the digital radiographs on monitor screens and paper prints 3 2 DATA ACQUISITION
37. IAEA RADIATION TECHNOLOGY REPORTS No 2 Development and Optimizatior a Low Gost System for Digital Industrial Radiology International Atomic Energy Agency IAEA RADIATION TECHNOLOGY SERIES PUBLICATIONS One of the main objectives of the IAEA Radioisotope Production and Radiation Technology programme is to enhance the expertise and capability of IAEA Member States in utilizing the methodologies for radiation processing compositional analysis and industrial applications of radioisotope techniques in order to meet national needs as well as to assimilate new developments for improving industrial process efficiency and safety development and characterization of value added products and treatment of pollutants hazardous materials Publications in the IAEA Radiation Technology Series provide information in the areas of radiation processing and characterization of materials using ionizing radiation and industrial applications of radiotracers sealed sources and non destructive testing The publications have a broad readership and are aimed at meeting the needs of scientists engineers researchers teachers and students laboratory professionals and instructors International experts assist the IAEA Secretariat in drafting and reviewing these publications Some of the publications in this series may also be endorsed or co sponsored by international organizations and professional societies active in the relevant fields There are two
38. NATIONAL ORGANIZATION FOR STANDARDIZATION EN ISO 10893 12 2011 Non destructive testing of steel tubes Automated full peripheral ultrasonic thickness testing of seamless and welded except submerged arc welded steel tubes ISO 2012 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 11699 2 2012 Non destructive testing Industrial radiographic films Part 2 Control of film processing by means of reference values ISO 11699 2 1998 German version EN ISO 11699 2 2011 Foreign Standard INTERNATIONAL ORGANIZATION FOR STANDARDIZATION EN ISO 17636 1 2013 Non destructive testing of welds Radiographic testing X and gamma ray techniques with film ISO 2013 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION EN ISO 17636 2 2013 Non destructive testing of welds Radiographic testing X and gamma ray techniques with digital detectors ISO 2013 KAK A C SLANEY M Principles of Computerized Tomographic Imaging IEEE Press New York 1988 KONONV N K et al A digital system for production X ray images with a high spatial resolution Instruments and Experimental Techniques 45 5 2006 LINDLEY C A Practical Image Processing in C Acquisition Manipulation Storage J Wiley amp Sons New York 1991 MEADE B KIDWELL C WARREN G Reliability and cost study of digital radiography film and radioscopy ASNT Digital Imaging Topical 6 2003 OIS ENGINEERING Freshex A combined System for Ultrasonic an
39. RES vr seen eu bey p P ESO err webs esa d queste a d ied 3 1 Introduction to ISee software for image processing 0 ees 3 2 Data acquisition and image calibration procedure llli 3 2 1 Software and hardware installation 22222 llle 3 2 2 Software operation and image acquisition 0 0 0 0 3 2 3 Calibration of PHOLOBCODE ee naar E SS 3 3 Qualification procedures for fluoroscope qualification using Isee According to ASTM E 2597 3 3 1 Measurement procedure for basic spatial resolution SR 0 0 6 0 eee ee eee 3 3 2 Measurement procedure for efficiency SNRA i iesu edP REG PECORE vend 3 3 3 Measurement procedure for achievable contrast sensitivity and specific material thickness range v3 9od oo RE 22a TA e a an ae EHE 845 3 3 4 Identification Of radiographs a nn oh ca ae Rhee se RESO des ACQUISITION AND ANALYSIS OF RESULTS 3c 5222 49er ere neebeteaesebudanacoangeess 4 1 Measurements of basic Spatial resolution dew reg cob he Sed EOS SERE UH berre 42 Measurements of efficiency lt 4 242464554644066 50 66604440646 eed e 5400440806405 uu 4 3 Measurements of achievable contrast sensitivity and specific material thickness range 4 4 Comprehensive results 0 eR es 4 5 Comparison of results with those obtained from other digital industrial radiology methods 4 6 Experience with isotopic radiation sources 6 eee teen eens 4 7 Standa
40. SO 5579 1998 Non destructive testing Radiographic examination of metallic materials by X and gamma rays Basic rules ISO 1998 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 15708 1 2002 Non destructive testing Radiation methods Computed tomography Part 1 Principles ISO 2002 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 15708 2 2002 Non destructive testing Radiation methods Computed tomography Part 2 Examination practices ISO 2002 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 19232 1 2004 Non destructive testing Image quality of radiographs Part 1 Image quality indicators wire type Determination of image quality value ISO 2004 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 19232 2 2004 Non destructive testing Image quality of radiographs Part 2 Image quality indicators step hole type Determination of image quality value ISO 2004 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 19232 5 2004 Non destructive testing Image quality of radiographs Part 5 Image quality indicators duplex wire type Determination of image unsharpness value ISO 2004 INTERNATIONAL ORGANIZATION FOR STANDARDIZATION ISO 10893 1 2011 Non destructive testing of steel tubes Part 1 Automated electromagnetic testing of seamless and welded except submerged arc welded steel tubes for the verification of hydraulic leaktightness ISO 2011 INTER
41. STM E 1025 step holes ISO 19232 2 or wires ISO 19232 1 change the hole diameters or wire diameters with their thickness Therefore the hole or wire visibility depends on the image unsharpness and the achieved CNR If the hole diameter is much larger than the unsharpness the equivalent IQI sensitivity EPS defined by IQI thickness in of the penetrated material thickness for 2T hole visibility changes proportionally to about 1 SNR pop a b gt 2 ir Contrast in c 2 2 Signal base material base material Length Length Notch visible Notch not visible Contrast Noise is high Contrast Noise is low Signal Noise is high Signal Noise is low FIG 36 The influence of noise on the visibility of a notch in radiography a the notch is visible if the noise contribution can be neglected b the notch is not visible if the noise is just higher than the contrast Since the grey values of the pixels in the digital images assuming the signal is linear to dose depend on noise and signal intensity independent of the contrast and brightness processing for image viewing the SNR has been proposed and accepted as a value equivalent to the optical density and a certain film system in film radiography EN 14784 1 EN 14784 2 and ASTM E 2445 E 2446 Visibility details of flaws can be increased by the SNR of the DDA image in comparison with a digitized film image Fig 37 43 BAM 5 8mm steel Fuji IX25 SNR 265 nor
42. ailable X ray power and distances the frame exposure time should be long enough to have enough signal in the middle of the image At BAM an X ray tube up to 225 kV and 1 8 kW at a distance of 700 mm is used For this source a frame exposure time of 200 ms five frames per second unprocessed raw data was always the optimum shutter 1829 Table 6 provides typical shutter values and the corresponding frame exposure times calculated from the formula given in the user manual NET FOculus S user manual v1 15 001 pdf TABLE 6 FRAME EXPOSURE TIME OF THE CCD CHIP AND CORRESPONDING SHUTTER VALUE SETTING IN THE CAMERA SOFTWARE CONTROL TAB 1394 Shutter value Frame exposure time 1394 Shutter value Frame exposure time l l us 1729 0 1 ms 10 10 us 1829 0 2 ms 100 100 us 2129 0 5 ms 500 500 us 2422 I ms 550 I ms 2522 2 ms 650 2 ms 2822 5 ms 950 5 ms 2944 10 ms 1045 10 ms 3044 20 ms 1145 20 ms 3318 60 ms 1445 50 ms 3323 65 ms Figure 15 shows a snapshot of an ongoing flat field exposure This is an example of ongoing integration with V2 9 frames of 50 are already done using all features including calibration The acquired grey values of a single frame are between 14 and 129 so no clipping is shown and the source calibration should also work The computer load by the applied temporal filtering of five frames and image integration decreases the frame rate from five to two frames per second So an overall exposure time of 50 x 0 2 s 10 s is integrated
43. al Carbon Steel sQOL WWQOZ vVul8 AMM00Z 90 ZcL M dd 14 NEN e C SOOL 00 E ond NJOO 90 val EE 1anun NJ FJ JdODOSOYUON 14 IV LIDIG sgy WWOOZ YUS AxOOC 90 ZcL M 34 G4 fn NL il h MW e Od wwon sYHYer NIO0C 90 z M 34 danan NAF Wilda G3Z1LIDIG JPEG 90 Zeck M 34 NAN N3lNIO3dS 40 MOVE AO HdDVYOOLOHd 90 Z CL M 34 Nan NAWIOAdS 40 HdVHDOLOHd Discontinuities Cracks lack of penetration porosity lack of material undercut 53 st lt LLI lt o G WY D H o s O Specimen Weld Welding Process SMAW Joint Preparation Single V Ray Source X Nominal Thickness 10 mm Material Carbon Steel 009c OG Vulp AO 0 OLM 3H 13 Vd Wild Q3ZI LIOIG WD 00L VU AALLL 0 0LM H4 11 MVd NAWIOAdS 40 MOVE 40 HdavHoOLOHd 0 0L Mrdd MVd U701 5374 47H 47 ad N3lNIOddS 40 HdVeDOLOHd 54 Catalogue Test Sample IAEA 005 pum 0 Oo u o 0 i U Q pu CL 4 E O C LL O v Uu ov o O i A 0 amp 2 2 E E o EL WY Ray Source X Nominal Thickness 7 mm Material Aluminium soge WWOOZ WWZE A074 LO Z M_W 14 9HY F gt A m fe mr ser oe Zu Ze Zi Ze i elt veg p tt m 2 og Wilda G3ZILIDIG at sce WWOOZ Vulp AMS LO Z M IV NI 9HY NAWIOAdS 40 HdVHDOLOHd Discontinuities Vermicular pores longitudinal crack heavy metal
44. are at the corners with a distance to the edge of 10 of the effective digital fluoroscope range Fig 23 21 File View Image Mode Misc DO amp amp Nita HY DVO BAA Bele FIG 23 Areas to be measured 6 Calculate the mean signal of the 20 pixel x 55 pixel averaged areas over the same five locations in one of the non difference images This will be called the Mean GV first image no calibration is needed 7 Calculate the average in the same areas of an offset image without radiation This is called the Mean OV see Fig 19 8 Calculate the dSNRn value using the following equation Mean GV first image Mean OV v2 X 88 6 dS N Rn A 14 c difference image SR V2 exe is used without any pixel calibration because a difference image is used for calculation The basic spatial resolution SR from Section 3 3 1 is used for normalization 9 The dSNRn value obtained for the five different regions is averaged to obtain the final dSNRn value 10 A plot may be drawn between various values of dSNRn Y axis and the square root of dose X axis Straight lines showing linear behaviour of dSNRn with the square root of dose should be obtained for different radiation energies A typical plot is shown in Fig 24 from ASTM E 2597 and the one from the example is shown in Fig 25 The slopes of these straight lines define the efficiency of the detector The value to be reported is the
45. ases The maximum achievable SNR is the limiting parameter for the described compensation It depends on the detector efficiency and the detector calibration of DDAs or the structure noise of the imaging plates It also depends on the noise of the material s structure and the material s roughness Therefore the compensation by increase of the tube voltage is restricted depending on the detector and material properties and especially on the maximum achievable SNR in the radiograph Figure 38 a shows a typical example for the compensation of decreased contrast u by increased SNR A step wedge with ASTM E 1025 IQIs 2 was exposed at different X ray energies and mA min with a constant source to detector distance The visibility of the 2T hole denoted by 2 in Fig 38 b was achieved with increasing kV of the tube at shorter exposure times This cannot be achieved with X ray films since they will always be exposed to an optical density between 2 and 4 In this case the films of a given class always have the same SNR in a small range owing to its specific manufacturing process The increase of the tube voltage from 80 to 150 kV allows the reduction of exposure time down to 20 for DIR in the example shown in Fig 38 All thickness steps of the test object can be inspected with one exposure at 150 kV The steps with the smallest thickness are even radiographed with 2 1T quality Here the tube voltage increase yields a higher efficiency and an increased
46. ata acquisition and Pakistan also reported problems For these reasons neither was able to reach the values of the other countries TABLE 8 EFFICIENCY MEASUREMENTS FOR DIFFERENT RADIATION QUALITIES dSNRn at 1 mGy dose at detector entrance window Condition for 1 mGy Noise of l er Mean Efficiency Ionization gauge or standard Mean grey n offset dSNRn Count Tube dose meter deviation value vas MM ry Distance current Integration manufacturer difference first 8 mm time s first value at mA model image at image TAM I mG I mGy S y Efficiency dSNRn at 50 kV no material Argentina 1000 27 0 2 Berthold TOL F 388 20 14406 403 00 22 6 Germany 1000 6 4 PTW Unidos 962 32 3502 6 400 22 0 Malaysia 1100 10 7 u 29 1 1740 358 2 29 7 TW23331 0841 32 TABLE 8 EFFICIENCY MEASUREMENTS FOR DIFFERENT RADIATION QUALITIES dSNRn at 1 mGy dose at detector entrance window cont Condition for 1 mGy Noise of ee Mean Efficiency Ionization gauge or standard Mean grey a offset dSNRn Gaunt Tube dose meter deviation value value cde Y Distance current Integration manufacturer difference first 8 mm time s A first value at mA model image at image ase ec I mGy Syrian Arab 1000 4 40 Babyline 81 Eurisys 5 110 50 12 0 Republic measures France Efficiency dSNRn at 90 kV 30 mm Al Argentina 1000 20 3 0 85 Berthold TOL F 301 4 19 417 397 395 Germany 1000 10 24 PTW Unidos 387 51 840 6392 52 Pakistan 1000 4 59 10 0 U
47. aterial After passing through the material with thickness x we have intensity I the relationship between I and I being I x l5 e SEES 1 where u is the linear attenuation factor or absorption factor Intensity I has the usual meaning being the average of the Poynting vector S namely the quantity of electromagnetic energy traversing a unit of surface in a unit of time If monochromatic radiation is used u can be taken as constant In practice it is better to use the effective attenuation coefficient U which depends on the radiation energy the test specimen thickness because of radiation hardening and generation of scattered radiation in the object tube filters detector screens and the geometrical set up used for inspection this determines the scatter contribution The coefficient u will always be smaller than the theoretical u as obtained for the mono energetic narrow beam energy The effective attenuation coefficient u can be calculated from the following formula using NDT films with optical density proportional to the radiation dose Pas Pi E fa 2 Heg In where D is the optical density of the film fog and base Dn is the optical density inside the object investigated hole step etc D is the optical density at base material AW is the wall thickness difference between base material and the imaged object 1 3 2 Characteristics of film image 1 3 2 1 Optical film density The process of film b
48. ays Materials Evaluation 68 2010 163 168 EWERT U et al Optimization of Digital Industrial Radiography DIR Techniques for Specific Applications An IAEA Coordinated Research Project IV Conferencia Panamericana de END Buenos Aires October 2007 Argentinian Society of NDT 2007 http www ndt net article panndt2007 papers 151 pdf EWERT U et al Strategies for film replacement in radiography Film and digital detectors in comparison 17th World Conference on Nondestructive Testing Shanghai China 2008 International Committee of NDT 2008 EWERT U STADE J ZSCHERPEL U KALING M Lumineszenz Speicherfolien f r die Radiographie Materialpr fung 37 1995 474478 EWERT U ZSCHERPEL U Proceedings of the NAARRI International Conference on Applications of Radioisotopes and Radiation Technology in the 21st Century 2001 1 17 FLISCH A et al Industrial Computed Tomography in Reverse Engineering Applications Proc Int Symp on Computerized Tomography for Industrial Applications and Image Processing in Radiology Berlin 1999 BB67 CD Deutsche Gesellschaft f r Zerst rungsfreie Pr fung e V DGZFP 1999 45 53 GOEBBELS J et al Functionally Graded Porosity in Ceramics Analysis with High Resolution Computed Tomography Proc 103rd Annual Meeting of the American Ceramic Society April 2001 Indianapolis Indiana J Ceramic Transactions 129 2002 103 124 GONZALEZ R C WOODS
49. ays Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2698 10 Standard Practice for Radiological Examination Using Digital Detector Arrays Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2736 10 Standard Guide for Digital Detector Array Radiology Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2737 10 Standard Practice for Digital Detector Array Performance Evaluation and Long Term Stability Book of Standards Volume 03 03 ASTM International 2012 61 BAVENDIEK K et al New Digital Radiography Procedure Exceeds Film Sensitivity Considerably in Aerospace Applications 9th ECNDT European Federation of Non Destructive Testing Berlin 2006 BUENO C MATULA A D Digital Radiography for Gas Turbine Components Proceedings from ASM Gas Turbine Materials Conference 1998 Rosemont ASM International Materials Park OH 1994 119 122 CASAGRANDE J M KOCH A MUNIER B DE GROOT P High Resolution Digital Flat Panel X ray Detector Performance and NDT Application 15th World Conference on Nondestructive Testing Rome 2000 http www ndt net article wecndt00 papers idn615 1dn615 htm COMPANY COMECH Non Destructive Testing of Alumino Thermic Rail Welds Seminar on Radiographic testing and radiation protection Dortmund 2002 DOROBANTU V Double wall technique pipelines inspection using gamma rays NDT net March 2005
50. but the time needed for this integration is 50 x 0 5 s 25 s So a faster computer will save some overall exposure time FIG 15 Snapshot of an ongoing flat field exposure 21 3 2 3 Calibration of fluoroscope As shown in Fig 16 the calibration is controlled via a simple text file The content of the file used here is given as highlighted text in Fig 16 ai EditPad EE Insert bb 1 EditPad Copyright C 1996 1997 by FIG 16 Principle of fluoroscope calibration via text file containing keywords and image names used for grey value correction The keyword adjust black controls that the first image dark 200ms S0frames tif is used to subtract any dark offset from each of the following white images All the following images here only one image bright 200ms 5S0frames tif with a homogeneous exposure at the screen are used for pixel wise linear interpolation of the image to be calibrated for equalization of the individual pixel responses to provide the same median grey value of the calibration image More details on image calibration can be found in the documentation included in the ISee package see http www kb bam de ic There identical functions can be used via Image gt Adjust pixels A typical calibration text file for the BAM fluoroscope is given here adjust black Dark2 200ms 240s tif Fe5mm 220kV 1mA 700mm 200ms 180s tif FeSmm 220kV 2mA 700mm 200ms 120s tif Fe5mm 220kV 4mA 700mm 200ms 120s
51. cal density Dm 18 the quantity depending on the current of the X ray source the film to source distance exposure time t and some constants which are characteristic of the film used 1 3 2 2 Image contrast definition and granularity The quality of a radiographic image can be described in terms of three factors namely contrast definition unsharpness and image noise granularity All three of these important factors affect defect detectability Radiographic contrast is the density difference between areas of a radiograph Obviously an image becomes more discernible when contrast is increased Contrast depends on X ray energy radiation scatter conditions the type of film and film processing used and film density Definition refers to the sharpness or unsharpness of the image In general one can assume that a sharp image is of higher quality than a less sharp image Definition is dependent on the geometric condition of the radiographic set up focal spot size radiographic energy intensifying screens used type of film used and its development and or radiation imaging system used The image noise visible as granularity in the film image e g by using a magnifying glass of 10x depends on the film speed film sensitivity given by the film grain size during film manufacturing or film system class the development conditions and the exposure time or optical density For linear NDT films the normalized signal to noise ratio SNR calcu
52. ch and Testing Germany 91 No 22 5 IAEA International Atomic Energy Agency Where to order IAEA publications In the following countries IAEA publications may be purchased from the sources listed below or from major local booksellers Payment may be made in local currency or with UNESCO coupons AUSTRALIA DA Information Services 648 Whitehorse Road MITCHAM 3132 Telephone 61 3 9210 7777 Fax 61 3 9210 7788 Email service dadirect com au Web site http www dadirect com au BELGIUM Jean de Lannoy avenue du Roi 202 B 1190 Brussels Telephone 32 2 538 43 08 Fax 32 2 538 08 41 Email jean de lannoy infoboard be Web site http www jean de lannoy be CANADA Bernan Associates 4501 Forbes Blvd Suite 200 Lanham MD 20706 4346 USA Telephone 1 800 865 3457 Fax 1 800 865 3450 Email customercare bernan com Web site http www bernan com Renouf Publishing Company Ltd 1 5369 Canotek Rd Ottawa Ontario K1J 9J3 Telephone 613 745 2665 Fax 613 745 7660 Email order dept renoufbooks com Web site http www renoufbooks com CHINA IAEA Publications in Chinese China Nuclear Energy Industry Corporation Translation Section P O Box 2103 Beijing CZECH REPUBLIC Suweco CZ S R O Klecakova 347 180 21 Praha 9 Telephone 420 26603 5364 Fax 420 28482 1646 Email nakup suweco cz Web site http www suweco cz FINLAND Akateeminen Kirjakauppa PO BOX 128 Keskuskatu 1 FIN 00101 Helsinki
53. cted to the Mac Powerbook 11 4 5 6 7 8 12 FIG 5 The camera module Teil means part Screws for adjustment the Detail 13 objective s optical axis FIG 6 Detail No 13 with screws sticking out approximately 5 mm Continue assembling shielding and housing details according to the BAM drawings Leave the installation of the mirror and the fluorescent screen until the end to minimize the possibility of damage to them Carefully paste the first surface mirror detail No 12 on the pivot plate detail No 11 This can be done using two sided sticky tape Fix the plate bearing mirror at a 45 angle to the optical axis of the objective directed by the reflecting side to the place where the fluorescent screen will be installed The aluminium plate detail No 6 must be clean and smooth to avoid artefacts on the radiographic pictures If there are any scratches on any of its sides the plate should be abraded and if necessary polished possibly galvanically Carefully paste the fluorescent screen on the aluminium plate detail No 6 This can be done using two sided sticky tape 9 Before installing the fluorescent screen into the system the positions of the mirror and the objective can be adjusted by the implementation of some tests in visible light This can be done using a BAM adjustment target printed on thin paper and installed in place of the fluorescent screen Fig 7 BAM Raxiio5000 Adjustment
54. ctice for Computed Tomographic CT Examination Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E1742 E1742M 12 Standard Practice for Radiographic Examination Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2002 98 2009 Standard Practice for Determining Total Image Unsharpness in Radiology Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2007 00 Standard guide for computed radiology Photostimulable Luminescence PSL Method Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2033 99 Standard practice for computed radiology Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2422 11 Standard Digital Reference Images for Inspection of Aluminum Castings Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2445 and E2446 Qualification for computed radiology Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2445 05 2010 Standard Practice for Qualification and Long Term Stability of Computed Radiology Systems Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2446 05 2010 Standard Practice for Classification of Computed Radiology Systems Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E2597 07e1 Standard Practice for Manufacturing Characterization of Digital Detector Arr
55. d X ray Inspection of welds 15th World Conference on Nondestructive Testing Rome 2000 http www ndt net article wendtOO papers 1dn286 1dn286 htm 64 PATEL R J Digital application of radiography 3rd Middle East Non Destructive Testing Conference amp Exhibition Bahrain Manama 2005 Saudi Arabian Section of the American Society for Nondestructive Testing SAS ASNT and Bahrain Society of Engineers BSE 2005 REDMER B EWERT U ONEL Y BARANOV V Untersuchungen zur Optimierung der Aufnahmeanordnung f r die Tomosynthese und strukturabhangige Vorfilterung Jahreskonferenz der Deutsche Gesellschaft f r Zerst rungsfreie Pr fung e V DGZFP Berichtsband 1996 637 647 REDMER B et al Sensitive Detection of planar Defects by a Mechanised Radiometric Weld Inspection System 15th World Conference on Nondestructive Testing Rome 2000 http www ndt net article wcndt00 papers idn370 idn370 htm REIMERS P KETTSCHAU A GOEBBELS J Region of interest ROI mode in industrial X ray computed tomography NDT International 23 1990 255 261 RIESEMEIER H GOEBBELS J ILLERHAUS B Development and application of cone beam tomography for materials research Proc Int Symp Computerized Tomography for Industrial Applications Berlin 1994 Deutsche Gesellschaft f r Zerst rungsfreie Pr fung e V DGZFP 1994 44 112 119 SOLTANI P K WYSNEWSKI D SWARTZ K Amorphous Selenium Direct Ra
56. diographic film image is also given for comparison purposes Fig 34 b It should be highlighted here that compared with X ray imaging gamma ray imaging necessitated the use of additional shielding The gamma ray beam was collimated with the conventional tungsten collimator and additional shielding of lead of about 3 mm was provided around the DFS to ensure that radiation did not impinge on the CCD camera In addition lead bricks were placed on the front side to provide a window so that radiation was restricted to the ROI alone FIG 34 a Exposure of a 10 mm thick steel weld with Ir and a digital fluoroscope Sains FIG 34 b Exposure of the same 10 mm thick steel weld with 160 kV X rays and film The gamma ray image using the DFS was contrast stretched while the film image using X rays was subjected to high pass filtering to effectively show the defects in the specimen It can be observed from Fig 34 that porosity can be detected in the gamma ray image though not all could be detected A comparison of the image quality indicates that in the case of the DFS the duplex wire IQI of the 6D wire could be resolved indicating a larger 39 unsharpness of 0 25 mm compared with film While 1T could be resolved in the film the 10 4T can be resolved in the DFS image although with difficulty and processing However this is a major achievement as it clearly reveals the potential of the DFS for use with gamma rays This would be a real b
57. diography for Industrial Imaging DGZfP Symposium Berlin 1999 CD ROM VENGRINOVICH V L DENKEVICH Y B TILLACK G R NOCKEMANN C Multistep 3D X ray Tomography for a Limited Number of Projections and Views Rev Prog in QNDE THOMPSON D O CHIMENTI D E Eds Vol 16 Plenum Press New York 1997 317 323 ZSCHERPEL U et al Comparative analysis of radiological detector systems 8th ECNDT Barcelona 2002 Vol 1 No 12 NDT net 2002 ZSCHERPEL U et al Possibilities and limits of digital industrial radiology The new high contrast sensitivity technique Examples and system theoretical analysis Int Symp Digital Industrial Radiology and Computed Tomography Lyon France 2007 ZSCHERPEL U Film digitization systems for DIR Standards Requirements Archiving and Printing NDT net 5 5 2000 http www ndt net article v05n05 zscherp zscherp htm 65 Annex BAM CONSTRUCTION DRAWINGS FOR PRODUCING A CASING FOR THE DIGITAL FLUOROSCOPE The drawings reproduced in this Annex are for a typical low cost system for digital industrial radiology courtesy of the Federal Institute for Materials Research and Testing BAM Germany 67 68 IF Teil is German for part FIN dk ar Teil is German for part IN dh 69 70 M Teil is German for part ZA dk 71 12 M4x0 6H 155 00 4
58. e http www renoufbooks com Orders and requests for information may also be addressed directly to Marketing and Sales Unit International Atomic Energy Agency Vienna International Centre PO Box 100 1400 Vienna Austria Telephone 43 1 2600 22529 or 22530 Fax 43 1 2600 29302 Email sales publications iaea org Web site http www iaea org books LGG60 c L The introduction of powerful computers and reliable imaging technologies has had a significant impact on traditional radiation based non destructive testing NDT techniques In particular digitization of images provides economy of storage efficiency of communication and increased speed of inspection and evaluation NDT laboratories in developed countries are progressing rapidly with the digitization of radiation inspection data New imaging techniques using image intensifier systems imaging plates and flat panel detectors have increased the capacity for visualization of surface and internal defects in welds castings forging composite materials and concrete revealing new potential for accurate evaluation of such defects by radiation techniques This publication describes the design development and optimization of an affordable low cost digital industrial radiology DIR fluoroscopic system It provides guidelines on building an economically viable easily assembled DIR system providing interested Member States including developing Member States access to DIR techn
59. e IAEA on these publications Information may be provided through the IAEA web site by mail at the address given above or by email to Official Mail Qiaea org DESIGN DEVELOPMENT AND OPTIMIZATION OF A LOW COST SYSIEM FOR DIGITAL INDUSTRIAL RADIOLOGY The following States are Members of the International Atomic Energy Agency AFGHANISTAN ALBANIA ALGERIA ANGOLA ARGENTINA ARMENIA AUSTRALIA AUSTRIA AZERBAIJAN BAHRAIN BANGLADESH BELARUS BELGIUM BELIZE BENIN BOLIVIA BOSNIA AND HERZEGOVINA BOTSWANA BRAZIL BULGARIA BURKINA FASO BURUNDI CAMBODIA CAMEROON CANADA CENTRAL AFRICAN REPUBLIC CHAD CHILE CHINA COLOMBIA CONGO COSTA RICA C TE D IVOIRE CROATIA CUBA CYPRUS CZECH REPUBLIC DEMOCRATIC REPUBLIC OF THE CONGO DENMARK DOMINICA DOMINICAN REPUBLIC ECUADOR EGYPT EL SALVADOR ERITREA ESTONIA ETHIOPIA FIJI FINLAND FRANCE GABON GEORGIA GERMANY GHANA GREECE GUATEMALA HAITI HOLY SEE HONDURAS HUNGARY ICELAND INDIA INDONESIA IRAN ISLAMIC REPUBLIC OF IRAQ IRELAND ISRAEL ITALY JAMAICA JAPAN JORDAN KAZAKHSTAN KENYA KOREA REPUBLIC OF KUWAIT KYRGYZSTAN LAO PEOPLE S DEMOCRATIC REPUBLIC LATVIA LEBANON LESOTHO LIBERIA LIBYA LIECHTENSTEIN LITHUANIA LUXEMBOURG MADAGASCAR MALAWI MALAYSIA MALI MALTA MARSHALL ISLANDS MAURITANIA MAURITIUS MEXICO MONACO MONGOLIA MONTENEGRO MOROCCO MOZAMBIQUE MYANMAR NAMIBIA NEPAL NETHERLANDS NEW ZEALAND NICARAGUA NIGER NIGERIA NORWAY OMAN PAKISTAN
60. e preparation of this report The IAEA officers responsible for this report were Joon Ha Jin A A Khan B P C Rao and P Brisset of the Division of Physical and Chemical Sciences EDITORIAL NOTE This report has been edited by the editorial staff of the IAEA to the extent considered necessary for the reader s assistance It does not address questions of responsibility legal or otherwise for acts or omissions on the part of any person Although great care has been taken to maintain the accuracy of information contained in this publication neither the IAEA nor its Member States assume any responsibility for consequences which may arise from its use The use of particular designations of countries or territories does not imply any judgement by the publisher the IAEA as to the legal status of such countries or territories of their authorities and institutions or of the delimitation of their boundaries The mention of names of specific companies or products whether or not indicated as registered does not imply any intention to infringe proprietary rights nor should it be construed as an endorsement or recommendation on the part of the IAEA The IAEA has no responsibility for the persistence or accuracy of URLs for external or third party Internet web sites referred to in this book and does not guarantee that any content on such web sites is or will remain accurate or appropriate CONTENTS INTRODUCTIO S ee bho RS eed ee RP PEINE URS eee ESO EUN
61. e same pixel lines 2 Choose a source to detector distance of 21000 mm 3 Define conditions such as focal spot size no filters etc 4 Select the radiation energy e g 90 kV The current of the X ray tube is to be selected such that the grey value of the duplex wire IQI is 80 2 596 of full saturation for the fluoroscope In the example here the acquisition parameters of V2 using the FO442SB CCD camera in the fluoroscope were a Shutter 1829 corresponds to 200 ms frame time b Brightness 555 c Number of frames 500 d Temporal filter 5 5 Use Fig 18 and Eq 13 to calculate the SR 6 The measurement is to be carried out using a profile plot in ISee on an area of 60 of the lines of the duplex wires for profile integration averaged to avoid variability along the length of the wires Fig 18 Use the mouse cursor within Isee Version 1 10 2 to read the dip separation in per cent after marking of the 100 position at the dip maximum and the 0 position at the background between the wire pairs 7 The SR is calculated as the linear interpolation of the wire pair distances between the last wire pair with more than 20 dip between the wires in the pair and the first wire pair with less than 20 dip between the wires Fig 18 sR D Di P2 Ri 20 13 Ri R5 where D is the size of the smallest wire pair with gt 20 resolution of the gap D is the size of the largest wire pair with lt
62. e test specimen It is placed on the surface of the test specimen facing the source and then the exposure is made and the film is processed The minimum diameter of the wire visible on the radiograph is noted The sensitivity is then calculated as a percentage for example 1 2 4 etc The lower the percentage the better is the sensitivity for flaw detection 1 2 FILMLESS RADIOGRAPHIC TESTING METHODS 1 2 1 Limitations of the conventional film radiographic testing method Although film radiography presents high resolution images it suffers from several major disadvantages including the following Low efficiency leads to longer exposure times Radiographic films are not reusable Considerable film processing facilities are required Considerable time is required to develop the film and interpret the results Workers are exposed to hazardous chemicals during film development There are storage and retrieval costs for radiographs after inspection X ray film deteriorates over time Interpretation of radiographs is subjective There is difficulty in full automation 1 2 2 Film digitization Film digitization is not a filmless technology but it allows the use of all means of computer processing with traditional film exposures There are several types of film digitization system such as point by point digitization line by line digitization and array digitization The most commonly used is point by po
63. e testing NDT technology In its regular programme it supports continuous and effective transfer of NDT technology to developing countries These efforts have led to a stage of maturity and self sufficiency in this area in many countries NDT methods are primarily used for detection location and sizing of surface and internal defects in welds castings forging composite materials concrete etc NDT methods are also used in preventive maintenance of components in the nuclear aircraft and other industries and in civil engineering structures Thus NDT technology contributes significantly to the improvement of the quality of industrial products and the integrity of equipment and plant components It is especially important in developing Member States where resources are scarce and life extension of components is critical This has had a positive impact on the quality of industrial goods and services The introduction of powerful computers and reliable imaging technologies has had a significant impact on traditional radiation based NDT techniques In particular digitization of images provides economy of storage efficiency of communication and increased speed of inspection and evaluation NDT laboratories in developed countries are progressing rapidly with digitization of radiation inspection data New imaging techniques using image intensifier systems imaging plates and flat panel detectors have increased the capacity for visualization of defects and re
64. eing taken per day In any case the requirements given in the BSS 1 and elaborated in the Safety Guide 2 are still applicable The radiation protection regulatory body in a Member State where the use of DIR is being proposed will need to ensure that the DIR system and its use will meet all the radiation protection requirements of the Member State 6 CATALOGUE OF IMAGES Catalogues were prepared during the CRP to allow a comparison of the image quality obtainable from the DFSs with that of images from digitized films and from CR systems using imaging plates and image intensifiers Each catalogue comprises four images one image obtained from a photograph of the test specimen one from its fluoroscopic image one image using digitized films and one image from image intensifiers and CR systems The images were identified according to the details set out in Section 3 3 4 Many test specimens were fabricated by the participants These include welding and casting samples of steel and aluminium with real flaws Some examples of the collected catalogue images are provided in this section 49 uonezi ensiA JO peziuundo eBeuur 9 pue G p sdeis Joint Preparation Source X Ray JdODOSOHON 14 IVLIDIG uoNezI ENSIA JO peziuunao ebeuur y pue Z sdels JOGIM d3lS 14933185 SSAINIVLS Nominal Thickness 1 2 to 12 5 mm Welding Process LL LL z a LL I LL LLI U Lu onal Z lt L H U an 0
65. ember as default Cancel Ok FIG 21 Pixel arithmetics in the ISee software for calculation of the difference image File View Image Mode Misc OS Hua n a ven SS is samples in window 1176 NO information should be visible in the difference us ran image mean dev The two images were not taken with same 1671 2958 conditions SAP massuraments according to EM 18784 median single ine mean 1671 median single line stdev 29 40 unnnomeskzed SNA 56 8 basic spatial resoksion mmk B tla SL MN SO A A Sele Haul ane end Correct difference image horizontal gr Takethe stdev for calculation of efficiency ins EAS Resultis here Sigma 26 76 a eT 307 1000 1088 mean der mean clie 1002 24 76 4047 SAT een doodle n EAM FE medisn smie bre men lt 1002 medius single line shoe 24 80 e ROI lis uernomakzed SHR 404 Po LJ bate spatial netolutien mm Nomalised SNA z imi 14340 Gv 1021 FIG 22 b Correct difference image showing constant background without any details and homogeneous noise from the X ray photons 5 Compute the noise standard deviation in a 20 pixel x 55 pixel area over five regions of the difference image The mean value of these five standard deviations will be called the o difference image The five 20 pixel x 55 pixel areas are to be placed on the image such that one 1s at the centre of the image and four
66. enefit to field personnel as it would provide a low cost system with comparable sensitivity A spin off from this CRP was a study of the dependence of the attenuation coefficient u of the Ir gamma rays in steel Ir has many gamma lines 130 270 296 310 320 468 485 590 610 and 890 keV and is considered to be equivalent to a 600 kV X ray generator It is well known that u depends on energy E and penetrated material thickness x u U E x 17 During the course of the experimental measurements it was observed that u as a function of the thickness traversed by gamma rays is best described by the following two nonlinear functions for non collimated and collimated beams Here x is the thickness of the traversed steel and is measured in cm coefficients a and 5 have the units of u to be cm The fits have been made in the range of 0 1 cm lt x lt 8 cm In the case of a non collimated beam using Ir and radiographic films the following was obtained 0 090 0 003 Lt noncollimated 9 4787 0 0016 18 Vx For a collimated beam the following was obtained EE ED 19 x These enhance the accuracy of results and can be used to derive a wall thickness difference from intensity differences using the Penetrameter function of the ISee software 4 7 STANDARDS IMAGE QUALITY AND COMPENSATION PRINCIPLES 4 7 1 Introduction Since 2005 different standards for DIR have been developed and published The internati
67. erances must be within 0 1 k All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 Camera shielding part 15 material V2A gt LL Y 1 58 50 All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 Camera shielding part 16 material V2A 83 84 Camera shielding part 17 18 material V2A All tolerances must be within 0 02 Camera shielding part 19 material V2A All tolerances must be within 0 05 A Part 20 camera eb amp Q O MO o N MO A 85 86 0 60 T All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 M4x0 7 _ Part 22 stainless steel suspension spring M5x0 8 6H 0 660 1 All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 M4x0 7 6H 4 50 DURCH DIN 74 58 00 X 90 All surfaces must be finished angular and parallel to each other All tolerances must be within 0 05 Camera shielding part 25 26 material Lead 87 88 080 1 90 00 HE 4 20 DURCH DIN 74 8 00 X 90 All surfaces must be finished angular D and parallel to each other All tolerances must be within 0 05 90 00 4 20 DURCH DIN 74 8
68. erial thickness mm FIG 29 Example of an SMRT measurement for fluoroscope according to ASTM E 2597 16 For 2 sensitivity it should come out to be SNR gt 130 In the example in Fig 29 the specific material thickness range for 2 sensitivity is from 10 to 77 mm Al with 4 s exposure time 17 For 1 sensitivity applications a SNR 2250 should be achieved In the example in Fig 29 the SMTR for 1 3 3 4 1 2 3 4 5 6 7 sensitivity would be 10 56 mm at 16 s exposure time A summary of all results of the participating countries is given in Section 4 Identification of radiographs The following naming and indexing system is to be used for providing digital radiographs Country name XXX e g ARG PAK etc Method digital fluoroscope FL computed radiography CR image intensifier II film digitization FD Material e g SSt or Al Type of specimen e g weld W or casting C Thickness in mm e g 50 Serial number of specimen Exposure conditions kV mA source to detector distance integration time e g 200kV 50mAs 700mm 60s 31 4 1 MEASUREMENTS OF BASIC SPATIAL RESOLUTION 4 ACQUISITION AND ANALYSIS OF RESULTS All participating countries provided SR values based on the measurement procedure described in Section 3 3 1 The results are shown in Table 7 TABLE 7 BASIC SPATIAL RESOLUTION SR OBTAINED WITH THE DIGITAL FLUOROSCOPES Exposure conditions Source to Country Te
69. ess grey value of dark image without exposure and Shutter which determines the light exposure time of each camera frame None of the other parameters should be changed The correct settings are shown here for the BAM camera working at 200 ms exposure time shutter 1829 and a dark level of 1 2 grey values brightness 555 For details see the camera manual at NET FOculus S user manual v1 15 001 pdf If Brightness and Shutter are not set correctly images as shown in Fig 14 are acquired with clipped grey values zero value in blue maximum value of 255 in red Information kept in the marked blue and red regions is lost in the image and cannot by enhanced by any frame integration so it is important to set the Brightness level correctly This will avoid any blue coloured pixels showing grey values of zero The optimum setting is also shown in Fig 14 At Brightness equal to 555 the electronic background of the camera without light is between 1 and 2 grey values The exact Brightness value depends on the individual camera and its actual temperature Brightness 4 1555 Jo 0 1023 IE I fo 0 511 Auto Exposure r 50 D 100 Shutter i j1823 1 3843 Hue ID p Bie sient Hadar Pater E Saturation III d q x ok 0 0 Sharpness 4
70. esting Part 3 General principles of radioscopic testing of metallic materials by X and gamma rays CEN 2001 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 14784 1 2005 Non destructive testing Industrial computed radiography with storage phosphor imaging plates Part 1 Classification of systems CEN 2005 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 14784 2 2005 Non destructive testing Industrial computed radiography with storage phosphor imaging plates Part 2 General principles for testing of metallic materials using X rays and gamma rays CEN 2005 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 16016 1 2011 Non destructive testing Radiation methods Computed tomography Part 1 Terminology CEN 2011 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 16016 2 2011 Non destructive testing Radiation methods Computed tomography Part 2 Principle equipment and samples CEN 2011 62 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 16016 3 2011 Non destructive testing Radiation methods Computed Tomography Part 3 Operation and interpretation CEN 2011 EUROPEAN COMMITTEE FOR STANDARDIZATION EN 16016 4 2011 Non destructive testing Radiation methods Computed tomography Part 4 Qualification CEN 2011 EWERT U et al Digital Laminography Materialforschung 37 6 1995 218 222 EWERT U et al New compensation principles for enhanced image quality in industrial radiology with digital detector arr
71. f the DFS measured in normalized SNR per mGy radiation dose is dependent on the radiation energy and had a maximum at 100 kV The maximum SNR at this energy is between 40 and 80 as measured by the participating Member States for a dose of 1 mGy at the DFS screen neglecting the measurement artefacts The results of measurements of achievable contrast sensitivity varied much more between the different countries This is a result of differences in detector operation and especially in detector calibration This showed that experience and knowledge are necessary for optimum DFS operation The results for SMTR were the most different between the countries India reported extremely good results Argentina was also able to report reasonable material ranges The other countries had problems reaching the requested SNR values of 130 or even 250 and were able to achieve only low SMTR values The limitations in SR and SNR are the application limits of the DFS for NDT inspections The following subsections highlight these limits in more detail Besides the measurement results reported in this section a catalogue of images was prepared and collected from a variety of test samples acquired with the DFS as well as from other digital radiological detectors Some examples from this catalogue are provided in Section 5 4 5 COMPARISON OF RESULTS WITH THOSE OBTAINED FROM OTHER DIGITAL INDUSTRIAL RADIOLOGY METHODS Several measurements using CR systems were carried out by
72. fide This selection and the optimum scintillator thickness depend on the desired image unsharpness and radiation energies used 1 2 5 2 Direct X ray imaging with photo conductors Another way to record information regarding detection of electromagnetic waves is what is called direct imaging using for example amorphous selenium technology or crystalline CdTe technology Fig 3 X rays or gamma rays strike a photo conductor made of amorphous selenium or a CdTe layer which converts them directly into electric charge that is further converted to a digital value for each pixel Pixelated metal contacts pixel sizes down to 70 um are available and ball grid arrays are used to contact the photoconduction layer to the underlying CMOS or amorphous silicon readout electronics The transmitted X ray intensity at each detector element position in the detector array 1s converted to a digital output level and fed to a computer where the images from the individual slices and or projections are computed in a reconstruction process to form a three dimensional 3 D image of the specimen Digital Panel Technologies Indirect Imaging Direct Imaging X Ray X Ray ki Scintillation Screen of Cesium lodide EAE 4 Reod Qut Electronics d Reod Out Electronics FIG 3 Comparison of detection technologies for digital detector arrays 1 2 6 Computed tomography Computed tomography CT uses measurements of X ray transmission from many angles encirclin
73. g the test specimen to compute the relative X ray linear attenuation coefficients of small volume elements 3 D voxels and presents the data as a cross sectional or 3 D attenuation map The clear images of interior planes of an object are achieved without the confusion of superposition of features that is often found with conventional projection radiography In the typical source specimen film radiographic set up the film is replaced with a one dimensional 1 D or two dimensional 2 D array of radiation detectors For a 1 D detector array the X ray beam and the detector elements are collimated to a narrow slit and highly aligned to each other to define a slice plane in the specimen This slit collimation reduces scattered radiation from the inspected object and improves the reconstruction result of this fan beam CT which is important for high X ray energies with increased X ray scatter by the inspected object Faster inspection times can be realized by using a 2 D image detector digital detector array or flat panel and a cone beam X ray beam In this way a 360 rotation provides projection images of a complete specimen volume The disadvantage is the missing suppression of scattered radiation generated in the object which introduces artefacts in the volume reconstruction and reduces the contrast in the projections Either the test specimen or the source detector assembly can be translated and rotated to obtain projections from multiple angles The
74. ial thickness Taking this into account the DFS provides only the testing class A due to the limitation of image sharpness The missing sharpness proven by duplex IQI is compensated for by the additional wires seen as required in ISO DIS 17636 2 Test Weld BAM 5 Fine Cracks are visible CEN 462 3 e Wires requires W 14 e Wire W16 visible e Step Holes requires H5 visible H4 ASTM E1025 better 2 2T Duplex wire EN 462 5 ASTM 2002 Visible D 7 e SR 200um III um High pass filtered for better presentation FIG 32 DFS exposure of test weld BAM 5 8 mm mild steel weld after high pass filtering Figure 33 shows the radiographs taken with the DFS and the CR system of Durr HD CR35 NDT and HD IP Both of the exposures were carried out at 130 kV with 100 mA Figure 33 also shows the two digital radiographs in detail No major differences can be observed For better image evaluation a high pass filter of ISee enhanced details was applied The visual image evaluation shows that the CR image is noisier and the contrast to noise ratio enables a significantly better visualization of cracks in the DFS image despite the higher unsharpness 1 BAM Low Cost Fluoroscope vs Computed Radiography BAMB test weld 8mm Fe 130 kV 0 5 m FOD 100 mAs BAM fluoroscope 17 mA 6 sec ST VI IP D rr CR35V 10 mA 10 sec a b BAM Low Cost Fluoroscope vs Computed Radiography BAMS test weld amm
75. idered for film radiography in textbooks and standards Since modern DDAs and CR can have a much wider dynamic range compared with even the double film technique this parameter was introduced for manufacturer characterization of DDAs in ASTM E 2597 2 DESIGN AND CONSTRUCTION OF FLUOROSCOPIC SYSTEM FOR DIGITAL INDUSTRIAL RADIOLOGY 2 1 BAM CONSTRUCTION DRAWINGS FOR DIGITAL FLUOROSCOPE The construction drawings developed by Germany s Federal Institute for Materials Research and Testing BAM for producing a casing for the digital fluoroscope are provided in the Annex to this publication These are available in German Table 1 provides a translation into English German terms used in the drawings and their translation into English are given in Table 2 TABLE 1 PARTS OF THE HOUSING Part No Quantity Description Material Stainless steel XSCrNi18 10 ASTM Alloy Type 304 EN 1 4301 1 l Casing bottom plate UNS 830400 or similar 2 l Casing right plate X5CrNil8 3 1 Casing left plate X5CrNil8 4 l Casing top plate X5CrNil8 5 l Casing front plate X5CrNil8 6 l Input window Aluminium alloy 7 l Casing rear plate X5CrNil8 8 9 2 Bolts as part of handle X5CrNil8 10 l Handle X5CrNil8 11 l Mirror holder XSCrNi18 12 l First surface mirror purchased First surface mirror 13 l Holder of inner CCD camera casing XSCrNi18 14 l Flat spring XSCrNi18
76. in Fig 22 b is useful for further analysis 3mm Cull Hl dm V CY SG A A E s AE 1 z Bar Hre ened Taken image at 120 kV and 3 mm Cu horizontal i a a Stripes indicate that no calibration has been used this is UE m i is correct p Dosimeter in front of the fluoroscope is visible 17 183 Statistic window is taken for different positions but mean r meiner 1189 53 77 13 89 outside the dosimeter image a VUES Use center value mean 1189 here from statistics median singlene men 1183 window median single ine stdev 61 38 rv Re uernomakzed SHR 13 4 N basic spatial resoiution mm Noemaiiced SHA P Mari Recall i i FIG 20 One of the two raw images for dSNRn measurement and its characteristics NR ISee C Users Alejandro Documents Cnea IAEA O File View Image Mode 9 amp mu amp aeelmtia tsS Calculations will be made solely on pixel per pixel basis without any spatial relations between pixels First operand is always the current image which you see now Please select an operation and specify the second operand If necessary use scaling and offset addition from the normalization section of this dialog in order to get the result fitting in unsigned 16 bit integers ISee internal representation 2nd operand v 400mm f5 5mm 500fr 25 00mA tif ES Zero mean normally distributed random value with standard deviation Normalization Scale 1 0 Offset 1000 0 Rem
77. inclusions 55 U C LLI E o G D H 3 o fS O Joint Preparation Single V Source X Welding Process SMAW Specimen Weld Ray Nominal Thickness 9 5 mm Material Carbon Steel SOOL WWOOZ Vulg AX09l cO S6 M dd 14 NEN gt n cw SOOL 0074 svg ANOS CO G 6 M 34 13 NUN WOOL SYwY98 NOI 20 G 6 M 34 G N N IN 114 G3Z1LIDIG Place for image from image intensifier YIIHISNILNI JOYNI co 96 M 34 Nan MOVE ANY LNOS4 NAWIOAdS JO H4YADOLOHd Discontinuities Lack of penetration undercut porosity 56 1 2 3 4 5 7 SUMMARY A low cost DFS for DIR can be built within the planned cost of 5000 and a step by step procedure is given in this publication The DFS provides image quality comparable with that of other commercial industrial systems for DIR The achievable contrast sensitivity 1s better than or equal to that provided by computed radiography and digitized films in a certain material thickness range but is less than that provided by modern DDAs The attractive features of this system include the reduction of radiation dosage and inspection time protection of the environment resulting from the elimination of chemical processing long term storage of digital data without degradation digital data analysis quantitative defect detection and evaluation and easy digital data transmission Because of the compact design of the DFS it is sui
78. ing must have black matt painting inside to avoid harmful reflection Therefore the corresponding parts must be painted before the beginning of assembly 2 Start the assembly from the camera module Fig 5 Leave the fixing of the lead glass and its supports detail Nos 17 and 18 for the end of module assembly 3 Using adjusting screws and springs detail No 22 fix the objective s optical axis in the middle of the circular hole of the steel plate detail No 19 During this adjustment the screws may extend beyond the camera bearing plate detail No 13 Fig 6 In this case shorter screws may be used or additional hollows in lead detail No 30 should be drilled TABLE 3 ADDITIONAL ITEMS TO BE PURCHASED FOR COMPLETION OF THE DIGITAL FLUOROSCOPE Price per item in euros Item No Name description Supplier prices from 2008 excluding value added tax l Kyokko DRZ PLUS fluorescent Kasei Optonix Ltd 1060 Naruta Odawara 185 screen City Kanagawa 250 0862 Japan for one 197 mm x 294 mm Phone 81 465361027 Fax 81 465361151 sheet Email KOX0197 cc m kagaku co jp Web site http www kasei optonix co jp one 115 mm x 155 mm sheet is needed as input area 2 FOculus FO442SB 2 3 CCD New Electronic Technology NET GmbH 1810 Camera Lerchenberg 7 D 86923 Finning Germany Phone 49 0 88 0692340 Fax 49 0 88 06923477 Email info net gmbh com Web site http www net gmbh com 3 EO Megapixel fixed FL
79. int digitization in which the film is moved in front of a collection tube A laser beam with a wavelength of about 680 nm red with a fixed diameter approximately 50 um passes the film The diffuse transmitted light through the film is integrated by the collection tube and registered by a photo multiplier PMT on top of the collection tube During the scan the folding mirror moves the laser beam along a horizontal line on the film The film is moved with a speed of 75 lines per second The resulting voltage at the photo multiplier 1s proportional to the light intensity behind the film After logarithmic amplification 12 bit digitization yields grey values that are proportional to the optical density of the film Unlike in other digitization methods the laser scanner illuminates with focused light and measures the diffuse light intensity behind the film All other methods illuminate with diffuse light the film is illuminated with a diffuser and measure the light intensity that passes through film in one direction camera objective or human eye in traditional film inspection see Section 3 2 Because of a spatial resolution of better than 10 um and optical density of up to 5 high end digitization yields several new possibilities for conventional RT These include for example digital film archiving quantitative evaluation image processing automatic image evaluation remote image transfer and production of reference catalogues for flaw evaluati
80. is recommended to reduce the kV by 20 especially for radiography with an image intensifier and CR The suitable kV for the digital fluoroscope may be different and should be found by test exposures 47 ISO 17636 2003 E 400 FT X ray voltage AU LL IHT NAG TARN TINN HKN 1 3 amp 5 6 F890 20 30 amp 0 50 6070 100 mm Penetrated thickness w Key copgernickel and alloys siee titanium and alloys A d Mo aluminium and alloys Figure 20 Maximum X ray voltage for X ray devices up to 500 kV as a function of penetrated thickness and material FIG 40 Recommended energy for exposure according to ISO 17636 1 4 7 8 Overall conclusion about image quality 48 The image quality in digital radiography is predominantly determined by the CNR Optimizing the contrast without considering the noise in digital radiography is not useful The maximum permitted X ray voltage for film radiography EN 444 EN 1435 ISO 5579 ISO 17636 can be exceeded in digital radiography The increase of X ray tube voltage above the limit of EN 444 improves the image quality of digital radiographs taken with very well calibrated DDAs and a DFS above the quality level of the best NDT films because of the increase of SNR compensation principle I The image unsharpness limits the perception of small and linear structures only partially and can be compensated for by increased SNR compensation principle II Wires can al
81. is to be carried out after calibration but before image processing with any digital filter For measurement of SNR and SNRn a 20 pixel x 55 pixel window is to be used For higher accuracy a 20 pixel x 200 pixel window can be used The IQIs listed in the following subsections are to be used 4 7 2 1 Wire IQI in accordance with ISO 19232 1 The requirement of the visibility of wires is to be selected in accordance with ISO 19232 3 or ISO 17636 or EN 1435 testing class A see Table 14 The wires to recognize are to be selected in agreement with the nominal wall thickness for weld inspection The wire IQIs are to be placed nearest to but not crossing the weld The wires are to be positioned 90 to the weld The visibility of the wires is to be read nearest to the weld and the smallest visible wire is to be at least two thirds visible over its full length For best presentation in the catalogue the single wire IQI is to be placed above the weld and the duplex wire IQI is to be placed below the weld but both on the source side The IQIs for casting inspection are to be placed at the thickest and thinnest area of the specimen 4 7 2 2 Plate hole IQI of ASTM E 1025 A 296 wall thickness is to be used for thickness selection ASTM E 1742 The required radiographic sensitivity is 2 27 These IQI are to be used with shims for wall thickness compensation to the real thickness of the weld if the thickness of the weld exceeds the nominal thickness by mo
82. l TIFF imge 2 should work with all cameras which have standard DirectShow Windows driver This software is licensed under terms and conditions of GNO General Public License as published by Free Software Foundation 2 is designed and written by Dr Oleksandr Aleksevchuk oleksandr aleksevchuk bam de in German Federal Institute Far Materials Research and Testing BAM Please visit the project page at http une kb bar del alextv2 For recent updates and additional information You are currently using a version build an Jul 21 2009 codename LUNAR FIG 12 About window for the BAM V2 exe software with information on licence and availability There can be several circumstances in which the V2 exe program simply crashes This can be caused by software bugs between the public domain library used for Video I O and the DLLs provided by the camera manufacturer This is outside the V2 exe program and cannot be prevented completely It can also happen that the camera is recognized but no data are transferred 0 frames per second and a black image window This occurs mostly after reconnection of the camera to the system In this case start the FOcontrol exe application and start and stop the camera as shown in Fig 10 After exiting the FOcontrol exe the program V2 exe should start smoothly and display the correct camera live data as shown in Fig 11 The first line View in V2 exe allows configuration of the image display in the main
83. lackening can roughly be described as follows The electromagnetic waves or free electrons generated by lead intensifying screens under X ray exposure impinge the film and set free electrons from negative Br ions These electrons are captured by electron traps so the free positive Ag ions are attracted by these negative centres becoming neutral and blackening the film after development The number of neutral Ag atoms formed on the film is directly proportional to the number of electromagnetic waves incident on it The optical film density achieved depends on the radiographic exposure or the radiation dose received by the film measured by the tube current or source strength multiplied by the time of exposure The optical density D is the degree of blackening of the film after development and fixing It is also called the film response to the dose of radiation and is expressed as D log L L 3 where L is the diffuse light intensity luminance measured on the image viewer L isthe diffuse light intensity luminance measured on the film on the viewer The IQI sensitivity achieved in the final radiograph depends on the value of achieved optical density D The number of photons incident on film is the number of photons that have traversed the material to be studied and according to Eq 4 1s exponentially decreased as a result the film s blackening density can be written as Died ge M 4 where D is the film blackening or opti
84. lated from the following film system parameters at an optical density of 2 can be orm SNR orm log e IG 05 5 where G is the film gradient at an optical density of 2 o is the film granularity at an optical density of 2 G o isthe gradient to noise ratio for films SNR can be calculated from the curves drawn between gradient to noise ratios and the square root of the dose or exposure However at the limit of detection the quality of the image depends on all three factors contrast unsharpness and granularity 1 3 3 Characteristics of digital image 1 3 3 1 Signal to noise ratio The optical film density and granularity are defined for films only If film is replaced with other detectors equivalent detector properties must be considered The image obtained by digital detectors is described in terms of grey levels which is a kind of darkening or blackening depending on the visual presentation of an image display The exposure to the digital detectors by the image forming radiations produces a grey level as digital pixel value numbers in the digital image This can be defined as the signal of the detector The grey level variations produced by fluctuations of the signal intensities of the different detector elements due to quantum statistics of X ray radiation and or electronic noise sources can be referred to as noise or grey level variations The detector response can then be measured in term
85. m Images high pass filtered for better presentation d PerkinElmer 1620 SNRiom 1500 Mag 3x Micro Focus FIG 37 Effect of increased signal to noise ratio of digital detector array image in comparison with digitized film image 4 7 4 2 High contrast sensitivity technique Four typical noise sources arise in radiography Photon noise depending on exposure dose e g mA s or GBq min Structure noise of detector fixed pattern noise Crystalline structure of material e g nickel based steel mottling Surface roughness of test object The first two noise sources can be influenced by the exposure conditions and detector selection The SNR of images achieved depends on the exposure dose low dose application The SNR increases with the square root of mA min or GBq min due to the improved photon quantum statistics The structure noise of films and imaging plates depends on the manufacturing process and can be influenced by the selection of the specific detector type e g fine or coarse grained film Film development and imaging plate scanner properties also contribute to the final noise value The structure noise of detectors and all noise sources depending on the object properties determine the maximum achievable SNR and therefore limit the image quality independent of the exposure dose high dose application Only with DDAs and a DFS can the structure noise due to different properties of the detector o
86. nce been extended by the World Intellectual Property Organization Geneva to include electronic and virtual intellectual property Permission to use whole or parts of texts contained in IAEA publications in printed or electronic form must be obtained and is usually subject to royalty agreements Proposals for non commercial reproductions and translations are welcomed and considered on a case by case basis Enquiries should be addressed to the IAEA Publishing Section at Marketing and Sales Unit Publishing Section International Atomic Energy Agency Vienna International Centre PO Box 100 1400 Vienna Austria fax 43 1 2600 29302 tel 43 1 2600 22417 email sales publications iaea org http www 1aea org books O IAEA 2013 Printed by the IAEA in Austria July 2013 STI PUB 1561 IAEA Library Cataloguing in Publication Data Design development and optimization of a low cost system for digital industrial radiology Vienna International Atomic Energy Agency 2013 p 30 cm IAEA radiation technology reports series ISSN 2225 8833 no 2 STI PUB 1561 ISBN 978 92 0 1293 10 7 Includes bibliographical references 1 Radiography Industrial Instruments 2 Nondestructive testing Cost effectiveness 3 Radiation Safety measures I International Atomic Energy Agency II Series IAEAL 13 00827 FOREWORD The International Atomic Energy Agency IAEA promotes industrial applications of non destructiv
87. o low IQI suppliers for worldwide distribution http www wilnos de request IQI manufactured by Kowotest clear IQT http www ie ndt co uk old version in yellow colour This problem has not been solved yet BAM is working on it Only one V process can access the Direct Show library per device more processes running on the same computer do not show any image data Check if the computer has the minimum specifications and operating system as recommended in the V2 manual Reinstall the software and hardware according to manufacturer instructions Follow the guidelines of the V2 manual exactly Check Windows Direct Show version and try other ones As a final option reformat the hard disk and reinstall Windows e g WinXP SP2 be aware of potential data loss Incomplete driver installation by FO control software installation process or FireWire hardware issues Try another computer with 32 bit Windows version and working FireWire connection providing 12 V to the camera Select a camera of equivalent specifications with USB connection Follow procedures or protocol for image analysis included in this publication TABLE 4 PROBLEMS ENCOUNTERED AND THEIR SOLUTIONS cont Problem encountered Solution Difficulties in image analysis or lack of functions in software Updates of ISee software http www kb bam de alex ic index html Latest ISee manual http www kb bam de alex ic ic manual v1 10 pdf Updates of V2 software http w
88. ology INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA ISBN 978 92 0 129310 7 ISSN 2225 8833
89. on 1 2 3 Fluoroscopy and radioscopy In the typical source specimen film radiographic setup the film is replaced with a fluorescent screen that emits visible light when exposed to radiation The screen which contains the image of the test specimen can either be read by direct viewing or be photographed by a camera fluoroscopy Alternatively instead of a fluoroscopic screen an image intensifier with a built in scintillation screen can be used to enhance the brightness of the input image as compared with a fluorescent screen The intensified light image at the exit screen of the image intensifier 1s coupled via mirror lenses to a charged coupled device CCD camera to photograph the image radioscopy This CCD camera converts visual signals to electrical signals that can be fed to a computer where they can be processed and analysed The light intensification of the image intensifier allows inspection of moving objects in real time e g 30 images per second see also Section 3 2 1 2 4 Computed radiography with imaging plates Direct digitizing systems accelerate the application of intelligent procedures to facilitate and enhance image interpretation For almost ten years imaging plate systems have been available for NDT and these can be used as a filmless radiography technique also known as computed radiography with imaging plates In the 1980s a step forward was made in medicine by using imaging plates able to store the image elimina
90. onal standards committees started with computed radiography Most of these standards are now under revision In 2010 the first practice on radiography with DDAs was published by ASTM International ASTM Similar standards are now under development at the European Committee for Standardization CEN and International Organization for Standardization ISO Table 12 provides an overview of present applicable RT and CT standards and the proposals that can be used for radiography with the developed digital fluoroscope TABLE 12 STANDARDS FOR RADIOGRAPHY WITH THE DIGITAL FLUOROSCOPE Standard Application CEN EN 13068 Radioscopy CEN prEN 16016 parts 1 4 NDT radiation methods CT ASTM Digital Detector Arrays Manufacturing Characterization E 2597 Practice E 2698 Guide E 2736 Performance Evaluation and Long Term Stability E 2737 ASTM E 2422 Digital catalogue of light alloy casting digitized from ASTM E 155 films ISO ISO FDIS 10893 7 NDT of steel tubes Digital RT for inspection of longitudinal and spiral welded seams ISO ISO DIS 17636 2 NDT of welds Digital RT for film replacement ISO ISO 15708 parts 1 2 NDT radiation methods CT Table 13 provides guidance on how digital detectors can be used for film replacement All film standards worldwide require that a minimum optical film density be exceeded The equivalent value in digital radiography is the linearized SNR Also in digital radiography IQIs are to be used These are basically
91. ose and record the mA s values required to achieve these dose levels prior to placing the digital fluoroscope The radiation qualities to be used for this measurement may be selected and documented The radiation quality used for the example measurements was as follows 60 kV the standard requires 50 kV 90 kV 20 mm Al 120 kV 38 mm Al the standard requires 40 mm and 135 kV 4 mm SSt the standard requires 120 kV and a 3 mm Cu plate The material required to adjust the radiation quality has to be placed at the tube port of the radiation source The ionization gauge used for measuring the dose rate is to be calibrated as per the manufacturer s recommendation 25 4 26 Two images are collected for each dose and each filter under identical conditions immediately after one another A correct example showing the attached dose meter is shown in Fig 20 The two images are used to calculate the noise without any fixed pattern noise or other potential anomalies through a difference image only the quantum noise is retained in this difference image The difference image can be obtained with ISee v 1 10 2 applying the subtract function from pixel arithmetics see Fig 21 An offset of 1000 should be added to this difference to avoid any clipping of noise values below 0 An example of what cannot be used as a difference image is shown in Fig 22 a something was changed in the data acquisition of the two images only an image as shown
92. osures with a higher dose provide significantly better contrast sensitivity than do short exposures A typical exposure 220 kV 8 mm Cu of an X ray film system C5 e g Agfa D7 Kodak AA400 requires about 3 6 mGy at the film The DFS at 220 kV and 10 mGy provides a dSNRn of about 80 in screen centre The C5 film system AGFA D7 provides a dSNRn of only 56 From this number it can be derived that the fluoroscope centre part of the input screen can provide the same contrast sensitivity as the C5 film system in half the exposure time Due to the significant reduction of the DFS sensitivity at the outer rim of the fluorescence screen it is recommended to use the DFS with the exposure conditions as given in exposure charts for C5 film systems at 220 kV to achieve comparable image quality This was experimentally verified for aluminium and steel DFS exposures after proper calibration provided radiographs with the same or even more visible wires than those from digitized C5 films Experiments were carried out to compare the quality of CR and DFS radiographs with the BAM test weld BAM 5 8 mm mild steel Figure 32 shows the DFS exposure of BAM 5 It can be seen that the radiograph shows more wire and step hole IQI values than is required for class B testing of ISO 17636 EN 462 3 EN 1435 and ASTM 1742 2 The new ISO DIS 17636 2 proposal requires achieving some minimum IQI values for wires or step hope IQIs and the duplex wire IQI depending on the mater
93. overall cost of the DFS is quite comparable among the various Member States For purposes of comparison the costs of commercial DIR technology such as film digitization computed radiography flat panel and image intensifier in selected Member States are also given in Table 5 It should be highlighted that a DFS can be built at a cost of about 5000 This is about 10 20 of the cost of comparable commercial DIR systems that provide similar image quality TABLE 5 COST OF DIGITAL INDUSTRIAL RADIOLOGY SYSTEMS EUROS IN SELECTED COUNTRIES AT THE TIME THE COORDINATED RESEARCH PROJECT WAS CARRIED OUT Fluoroscope housing Film digitization Computed Count and shielding as nee a Flat panel Image BAM design optical y Srapay manufacturer intensifier i manufacturer manufacturer components Argentina 2000 2882 4882 32 000 77 000 45 000 Yxlon GE GE XRS 232 India 2000 2882 4882 50 000 55 000 60 000 40 000 Array 2905 HD CR 35 NDT Thales France Yxlon D rr NDT XRS 232 Malaysia 3000 2882 5882 45 000 60 000 50 000 Array 2905 HD CR 35 NDT FPDigit13 127 Durr NDT Balteau NDT USA Pakistan 2000 2882 4882 33 000 40 000 45 000 GE FS 50B CR 35 NDT GE system D rr NDT Romania 2000 2882 4882 Syrian Arab Republic 200 2882 3082 Uruguay 1900 2882 4782 Uzbekistan 400 2882 3282 a Internal costs 15 3 EXPERIMENTAL PROCEDURES 3 1 INTRODUCTION TO ISEE SOFTWARE FOR IMAGE PROCESSIN
94. r camera elements and fluorescent screen be corrected by a calibration procedure since the characteristic of each element can be measured quite accurately Figure 37 shows the effect of an SNR increase equivalent to a CNR increase on the visibility of fine flaw indication The digitized fine grained film provides an SNR of 265 in the base material region The DDA image was measured with an SNR of about 1500 It shows significantly finer flaw indications Digital fluoroscopes achieve SNR values between those of digitized films and DDAs In film radiography it 1s well understood that the image quality increases if the tube voltage is reduced In DIR it can also be observed that the image quality increases in a certain range if the tube voltage is increased 44 The higher photon flow X ray intensity behind the object increases the SNR in the detected image faster than the reduction of the contrast by the decreased transmission contrast also known as specific contrast or effective attenuation coefficient u This effect depends on the ratio of attenuation decrease to SNR increase see also Eq 20 since the product of SNR and u controls the contrast sensitivity in the digital radiograph The effect has been observed if DDAs and a DFS are used for film replacement Well calibrated DDAs and DFSs typically can be exposed at higher tube voltages than can films However too high a tube voltage may even reduce the attenuation faster than the SNR incre
95. rds image quality and compensation principles 0 0 een Aco ole MMPOOMCUON comes ou en bed ker aaa teens CREE See BF RE ae 4 7 2 Requirements for image quality in digital industrial radiology 4 7 3 Magnification technique susanne rer aei re kee ee be bau e mace eee ees NYDN tn utn tn U0 c b2 b2 NN 4 7 4 Compensation principle I 215 Compensation principle IL sua eek HR a4 nee nahen I ere pda dp 4 7 6 Application of compensation principle I 2 eee 2 757 Selection ar TUDE voltage s sam terio 48 enter ei eneren 4 7 8 Overall conclusion about image quality llle 5 RADIATION PROTECTION IMPLICATIONS OF INDUSTRIAL RADIOGRAPHY 6 CATALOGUE OF IMAGES seer cates ee EPSPNORN EUER EAE SURE UI EE EE NEE R8 UI CPP REPERENG Es m DIBLIOGRAPITY LGG ANNEX BAM CONSTRUCTION DRAWINGS FOR PRODUCING A CASING FOR THE DIGITAL FLUOROSCOPE CONTRIBUTORS TO DRAFTING AND REVIEW 43 45 47 47 48 49 49 57 59 61 67 9 1 INTRODUCTION 1 1 THE RADIOGRAPHIC TESTING METHOD Non destructive testing NDT methods including radiography are largely used for detection location and sizing of surface and internal defects in welds castings forging composite materials concrete etc The radiographic testing RT method consists in passing a beam of radiation from a source X rays or gamma rays through a test specimen and detec
96. re than 20 TABLE 14 MINIMUM REQUIREMENTS OF ISO DIS 17636 2 TESTING CLASS A ON IQI REQUIREMENTS FOR DIGITAL RADIOGRAPHY cont Wire number Specified wall Duplex IQI Specified wall dameler min Specified wall Hole number E s Wire di J thickness mm thickness mm diameter mm Unsharpness d nd mm spacing mm pe 1 2 Wig t lt 2 H5 52 D11 0 080 0 063 0 20 0 16 122 02 2 W17 2 55 H4 2125 D10 0 100 0 08 0 25 0 20 41 TABLE 14 MINIMUM REQUIREMENTS OF ISO DIS 17636 2 TESTING CLASS A ON IQI REQUIREMENTS FOR DIGITAL RADIOGRAPHY cont i i Duplex IQI Specified wall Bikes Specified wall Hole number Tr E di J thickness t mm thickness t mm diameter mm Unsharpness x a E mm spacing mm 2 lt t lt 3 5 W 16 3 5 lt t lt 6 H5 5 lt t lt 10 D9 0 130 0 10 0 32 0 26 3 9 9155 W15 6 lt t lt 10 H6 10 lt t lt 25 D8 0 160 0 13 0 40 0 32 were W14 10 lt f lt 15 H7 29 199595 D7 0 200 0 16 0 50 0 40 7 lt t lt 10 W13 15 1x24 H8 358 f D6 0 250 0 20 0 64 0 50 10 lt r lt s15 W12 24 lt t lt 30 H9 0 25 0 80 151 25 WII 30 lt t lt 40 H10 0 32 1 00 25132 W10 40 tx 60 H11 0 40 1 25 32 lt t lt 40 W9 60 t H12 a 0 50 1 60 40 lt t lt 55 WS b 0 63 55 1 W7 b 0 80 Duplex IQI should be used in conjunction with either a wire or step hole IQI gt Duplex IQI should be examined using a profile display the largest wires which have a dip separation below 20 between the wire pair determine the un
97. ruguay 1000 8 52 Inovision 451B SI 3 450 370 37 5 Efficiency dSNRn at 120 kV 40 mm Al Argentina 1000 3 93 1 2 Berthold TOL F 540 4 33 624 446 38 5 Uruguay 1000 8 38 Inovision 451B 7l 4 432 369 35 9 Efficiency dSNRn at 120 kV 3 mm Cu Argentina 1000 14 95 1 2 Berthold TOL F 494 5 28 016 435 34 9 Germany 1000 5 22 PTW Unidos 402 52 102 6385 50 4 PTW Unidos Malaysia 1100 10 10 TW2333 1 0841 26 94 2 670 373 53 4 Pakistan 1000 4 33 13 0 Uruguay 1000 8 44 Inovision 451B D 3 612 366 36 4 Efficiency dSNRn at 160 kV 10 mm Fe Argentina 1000 11 65 1 6 Berthold TOL F 412 3 17 137 407 25 4 PTW Unidos Malaysia 1100 10 10 TW23331 0841 27 32 2510 380 48 8 Pakistan 1000 4 33 9 5 Uruguay 1000 8 54 Inovision 451B 44 2 163 368 25 6 Efficiency dSNRn at 100 kV no material Argentina 1000 6 05 0 2 Berthold TOL F 470 4 24 761 420 32 4 PTW Unidos Malaysia 1100 10 10 TW23331 0841 31 29 2 410 364 2 40 9 Syrian Arab 1000 4 M Babyline 81 Eurisys 39 93 50 M Republic measures France Polimaster Uzbekistan 1000 4 5 8 JIKT PM1621 54 6 580 300 64 6 Efficiency dSNRn at 220 kV 8 mm Cu Germany 1000 4 8 6 PTW Unidos 789 53 845 6405 26 6 Uruguay 1000 8 18 Inovision 451B 101 4 261 367 24 The efficiency of the digital fluoroscope depends on the X ray energy Figure 30 shows the measured dependence of the efficiency dS NRn in the centre of the fluoroscopic screen from the radiation energy 33 BAM Fluoroscope Efficiency Lo o co o
98. s of the signal to noise ratio SNR Since imaging plates and digital detector arrays DDAs are linear detectors their image quality can be characterized by this SNR For quantum limited detection the SNR will improve the square root of the X ray exposure and the signal grey level is proportional to the exposure mA s Thus the requirement for a minimum SNR in the image of digital detectors is equivalent to the requirement for a minimum optical density of film The SNR of a film can be derived from the film system class and the film density 1 3 3 2 Contrast to noise ratio The contrast C in grey values of IQIs and flaws is defined as the difference between the radiation intensities measured with a detector which 1s given as STE NEEDS 6 The relative contrast C which is mainly used for digital systems is normalized to the radiation intensity at a given area in the radiation image C AIT 7 For very small thickness changes differential it can be derived from the attenuation law using u in 1 mm eff C IAW 8 The specific contrast C is now defined as detector response which is AI per thickness change grey values per mm C C Aw Ij 9 Here I is the radiation intensity at a specific pixel area in a radiographic image The grey values of linear detectors as well as the grey value difference increase with increasing exposure time dose Therefore the detector signal S for a given radiation inten
99. sharpness 4 7 2 3 Duplex wire IQI in accordance with ASTM E 2002 or ISO 19232 5 or EN 462 5 The first unresolved wire pair is to be achieved in accordance with Table 14 The IQI Fig 35 is to be positioned nearest to the weld but slightly tilted by about 2 5 to the horizontal or vertical detector orientation PARTA FIG 35 Duplex wire type image quality indicator 4 7 3 Magnification technique If the required duplex wire indicated in Table 14 cannot be achieved and the compensation cannot be applied a magnification technique is recommended Before this is used it is to be determined whether the focal spot and distance cause additional unsharpness A larger source to detector distance and a smaller focal spot will reduce the unsharpness 42 4 7 4 Compensation principle I 4 7 4 1 Compensation of reduced contrast ui by increased SNR The image quality in DIR depends on the product of effective attenuation coefficient u also called specific contrast and the SNR This applies for CR DDAs DFs and X ray film Figure 36 illustrates the effect of noise on flaw detection The specific contrast to noise ratio per wall thickness difference Aw which is the essential parameter for the visibility of flaws and IQIs of a given size can be calculated from the detector response SNR as a function of exposure dose as follows small flaws only see Fig 36 and Section 1 3 3 CNR Aw SNR jug 20 Typical IQIs as plate holes A
100. sity linear to dose determines the contrast of a flaw or IQI in any radiographic image as follows C Slag 10 The perception of a certain flaw or IQI in an image depends not only on the C but also on the image noise Flaws and IQIs are only discernable if the contrast is higher than the image noise Wires and lines are visible if the contrast to noise ratio CNR is about one pores and IT holes are visible if the CNR is greater than 2 5 Higher exposure dose increases the CNR proportionally to the square root of dose or exposure if the detector responds linearly to dose and no other noise sources contribute to the image The CNR which is the essential parameter for the visibility or detectability of flaws and IQIs can be calculated from the detector response SNR as a function of signal and dose as follows small flaws CNR w SNR Yu 11 Therefore the image quality depends on the u and the detector response SNR This applies to all linear X ray image detectors and NDT film systems The CNR is inversely related to the contrast sensitivity which is normally measured as a percentage of detectable wall thickness difference 1 3 3 3 Basic spatial resolution The detectability of fine flaws depends on the detector unsharpness the geometrical unsharpness and the SNR or CNR If a magnification technique is applied the total image unsharpness is the combined effect of geometrical unsharpness and detector unsharpness divided b
101. so be seen in digital radiography at a high SNR if the basic spatial resolution of the detector or the geometrical unsharpness is greater than the wire diameter 5 RADIATION PROTECTION IMPLICATIONS OF INDUSTRIAL RADIOGRAPHY Industrial radiography is routinely used for the detection of defects in welds in engineering structures and components It is one of the major non destructive methods for imaging defects in material structures using X ray or gamma ray emitting radionuclides such as Ir and Co Exposure of any part of the human body to X rays or gamma rays may be harmful and this necessitates appropriate regulatory controls over the use of ionizing radiation for industrial radiography General requirements for protection and safety are given in the Radiation Protection and Safety of Radiation Sources International Basic Safety Standards BSS 1 with more specific guidance in the IAEA Safety Guide on Radiation Safety in Industrial Radiography 2 The low cost DIR system described in this report reduces the typical exposures needed to produce an acceptable radiographic image to about 10 50 of that needed for film based industrial radiography This should result in lower occupational doses per image all other factors being the same Whether this translates into lower occupational doses overall such as per year will depend for example on whether the lower exposures needed to produce an image lead to an increase in the number of images b
102. st specimen detector Nominal Prefer focal spot KV distance nn if any mm Argentina Duplex IQI 1000 3 No 100 Germany Duplex IQI 1000 3 9 No 90 India Duplex IQI 1000 eo No 90 Malaysia Duplex IQI 700 3 No 225 Pakistan Duplex IQI 1000 1 6 No 100 Romania Duplex IQI 700 3 No 200 Syrian Arab Republic Duplex IQI 700 1 5 No 200 Uruguay Duplex IQI 700 2 3 No 120 Uzbekistan Duplex IQI 1000 3 No 160 Smallest wire Largest wire mA No No gt 20 dip lt 20 dip 30 D6 D7 1 D6 D7 1 D6 D7 3 D6 D7 4 D7 D8 4 5 D6 D7 4 D7 D8 8 D6 D7 4 5 D6 D7 Measurements Basic spatial resolution SR um 200 190 200 200 190 200 180 200 200 QI at detector front surface Averaged and rounded The average SR of all manufactured fluoroscopes was 200 um This corresponds to the expected value from the fluorescence screen manufacturer Thus the optics and data acquisition hardware have an adequate fit to the screen unsharpness 4 2 MEASUREMENTS OF EFFICIENCY The measurement of the dSNRn is required to evaluate the efficiency of the developed fluoroscope and to compare it with the commercially available digital detectors fluoroscope computed radiography DDAs and digitized film The measurement procedure is described in Section 3 3 2 Table 8 summarizes the measurement results obtained by the Member States that took part in the CRP The results are very similar despite the fact that the Syrian Arab Republic used only 8 bit d
103. system to detect flaws usually referred to as sensitivity of flaw detection depends on a number of factors Most of these can be attributed to all three components of the system the source the specimen and the film These factors can be briefly listed as 1 Type of specimen its geometry shape thickness physical density type location and orientation of defects with respect to the direction of the beam 2 Energy of radiation and source size 3 Scattered radiation filters if used source to film and specimen to film distances 4 Type of film its definition contrast and graininess film processing and optical density viewing conditions intensifying screens 5 Operator s eyesight qualifications skill and experience Sensitivity is a general term used to describe the ability of a radiograph to show details in the image It 1s a reference to the amount of information or detail in the image For example if very small flaws can be seen in the radiograph it is said to have high or good sensitivity Radiographic sensitivity depends on image contrast definition and graininess Practically sensitivity is determined through the use of image quality indicators IQIs of which there are several kinds These include the wire type step wedge type and step and hole type In the wire type there are two classifications the single wire type and the duplex or wire pair type The IQI in principle should be of the same material as th
104. table for mobile inspection of welds and castings The concept of a low cost DIR system has the potential for use in providing training in DIR technology The IAEA may wish to consider supporting such training centres in developing countries 57 REFERENCES 1 INTERNATIONAL ATOMIC ENERGY AGENCY Radiation Protection and Safety of Radiation Sources International Basic Safety Standards Interim Edition IAEA Safety Standards Series No GSR Part 3 Interim IAEA Vienna 2011 2 INTERNATIONAL ATOMIC ENERGY AGENCY Radiation Safety in Industrial Radiography IAEA Safety Standards Series No SSG 11 IAEA Vienna 2011 59 BIBLIOGRAPHY ASTM INTERNATIONAL E155 10 Standard Reference Radiographs for Inspection of Aluminum and Magnesium Castings Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E747 04 2010 Standard Practice for Design Manufacture and Material Grouping Classification of Wire Image Quality Indicators IQI Used for Radiology Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E1025 11 Standard Practice for Design Manufacture and Material Grouping Classification of Hole Type Image Quality Indicators IQI Used for Radiology Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E1441 Standard Guide for Computed Tomography CT Imaging Book of Standards Volume 03 03 ASTM International 2012 ASTM INTERNATIONAL E 1570 11 Standard Pra
105. teel 4 116 194 265 103 284 298 55 111 181 34 65 91 30 56 s l 20 38 67 of 4 oj 0 4 Romania LAL 1 65 68 70 55 61 59 49 52 57 sel 45 sij 42 52 53 33 40 46 of of of of of o Steel 18 87 129 150 69 101 127 32 46 53 18 30 35 11 19 23 7 12 14 0 13 25 of of o Syrian Arab Al 4 691156 256 61 103 178 44 57 102 22 40 47 12 19 26 7 16 21 ol 16 35 of 0 12 Republic Steel 4 72 158 208 4S 102 165 301 ep 96 28 4l 15 18 44 9 16 20 0 2 4 0 9 178 295 122 217 108 15 40 12 16 3 5 7 19 36 16 Uruguay ii aa tae Ca EKIERERRECECEEUNNCNM i5 sersa AE L1 Lr r cr rrr pk poc rj S Lr Tr p f Steel 45 32 32 32 aj 44 43 51 77 122 28 49 60 14 19 21 94 13 14 0 of of of of o Country Step Wedge Tube current The results obtained are highly dependent on the calibration procedure and the SNR reached at the single steps of the set wedges As expected the SMTR of the less absorbing aluminium material 1s higher than that of steel If the SNR measured at a specific step did not reach the minimum SNR value of 130 the corresponding wall thickness is outside the SMTR 4 4 COMPREHENSIVE RESULTS All Member States that participated in the CRP were able to construct assemble and operate the DFS as described in this report The DFSs of all participants achieved a similar basic spatial resolution of about 200 um p The efficiency o
106. tep hole IQI is increased by compensation for missing duplex wire resolution through SNR enhancement see EN 462 5 ASTM E 2002 and the requirements of EN 14784 2 Several new standards define minimum duplex wire values for specific applications e g ISO DIS 10893 7 ISO DIS 17636 2 Typically one higher smaller diameter see EN 462 1 single wire resulting in higher contrast sensitivity is to be seen through adjustment of parameters that increase the SNR if an additional duplex wire of spatial resolution is required in the system qualification for a given material thickness and application It was proposed in CEN TC 138 WG 1 that the compensation should allow a maximum 2 wires versus wire pair compensations The compensation should be applicable to plate hole IQIs as well This is still under discussion This effect has been proven with a PE XRD 1620 detector in combination with Y XLON s Image 3500 software Even at a magnification of 1 and a basic spatial resolution of 200 um pixel size the significantly higher SNR of the DDA allows the detection of crack indications that are hidden by noise in the film image with its much better basic spatial resolution SR of 40 um Figure 39 shows the radiograph of a No 13 wire IOI on an 8 mm steel plate The radiographs were high pass filtered for better graphical presentation The digitized film shows wire No 16 and the DDA image shows wire No 19 as being visible with wire No 19 having a diameter of 50 um
107. tests The application V2 exe was developed especially for data acquisition with the Radio5000 fluoroscope at BAM and released under GNU public domain This program does not require any installation simply start V2 exe from a suitable directory The V2 exe file requires some more dynamic link libraries DLLs to run as shown in Fig 10 There is no installation required simply start V2 exe and keep all four files in the same directory My2 exe 691 KE 18 07 2009 13 51 S QtCore4 dl 2 0351 KB 27 03 2008 18 38 55 otGuid dl o 955 kB 19 02 2008 21 29 minguwm10 dl IB KB 27 l2 2007 17 23 FIG 10 V2 acquisition program and its components The main window as shown in Fig 11 appears on the desktop after starting the application V2 exe Clicking the About button opens the window pictured in Fig 12 610x662 View Live View raw Fit ka View B bits dynamic 0 255 Source 1388x1040 m 6 49 fps gv 0 255 a EA Apply temporal filter Frame integration Store En Ld FIG 11 Main window of the V2 exe application with live camera image camera recognized as Device 0 image size 1388 pixels x 1040 pixels 8 bit grey values 0 255 in the live image frame rate 6 49 frames per second The V2 exe application uses standard Windows video streams via DirectShow and ActiveX In this way a wide range of video devices with live data streams are supported at the moment only with 8 bit colour or greyscale
108. the running Windows system The camera power has to be provided by the FireWire cable A standard six pin IEEE 1394 cable and connector at the computer provide this power the smaller four pin connectors found on laptops do not Here adapter cables from four pin to six pin with an additional power supply of 12 V should be used Caution Be sure to connect the six pin cable only side correctly With force the steel frame of the six pin connector can be expanded so that the cable turned 180 can be plugged in If power is then provided to the camera the exit circuit of the FireWire interface inside the camera will be destroyed and the camera will have to be sent for repair to the manufacturer NET GmbH Germany 3 2 2 Software operation and image acquisition As the next step start the FOcontrol application from the desktop link Select the set ups as shown in Fig 9 Clicking the start camera button will show a live camera image the stop camera button will erase this image 16 from the window If all works correctly stop the camera and exit FOcontrol For more information see the manual FOcontrol V3 0 7 0 manual pdf ES r control 3 0 8 0 i 0 NET GmbH FO4425B FF 42500101 o 138627040 Format Modell Bl Cam 0 F04425B 15 798 fps camera device m im 7 a P m BAMA Marte Zequaiiami Target z Dad rmm mai S FIG 9 FOcontrol exe demonstration application of NET GmbH for basic camera
109. thickness the specific contrast CSa can be calculated from Eq 16 as follows jac s 16 pr 29 median single line mean e medien single line stdev unnnormalized SNR basic spatial resoluton mm faz Normalised SNR 176 ef gu SAib 0 2 mm FIG 26 Step wedge evaluation for specific contrast CSa calculation area 2 5 groove FIG 27 Measurement areas for determination of the specific contrast CSa 12 Obtain values of CSa for different image acquisition times say 16 64 and 256 s 13 Draw a curve between CSa 96 of penetrated wall thickness and wall thickness for each material and exposure time see Fig 28 14 For calculations of SMTR first compute the normalized SNR for each step with ISee read the normalized SNR value 15 Draw a curve between SNR and wall thickness for each material and exposure time CSa Aluminium 160kV 21mA 1 20 1 00 0 80 et rn 0 60 4s N a P 0 40 bi Ge a ee m d 64s 0 20 b s meii at 0 00 CSa 10 20 30 40 50 60 70 80 90 100 Material thickness mm FIG 28 Example of a CSa measurement for fluoroscope according to ASTM E 2597 30 700 0 SMTR Aluminium 160kV 21mA 600 0 500 0 3 15 400 0 cc H 45 z uw 300 0 g 16s 64s 200 0 296sensitivity 6 196 sensitivity 100 0 4 0 0 T T T T T T T T l 10 20 30 40 50 60 70 80 90 100 Mat
110. thickness range based on the digital high CNR technique 4 7 5 Compensation principle II 4 7 5 1 Compensation of insufficient detector sharpness high unsharpness by increased SNR The EN 14784 2 standard requires the application of high definition CR systems for X ray inspection with pixel sizes of less than 50 um for class B inspection for wall thickness 12 mm and tube voltages 150 kV Most available digital systems do not allow a resolution below 50 um pixel size and are excluded for industrial X ray applications in Europe The recent trials have shown that DDAs and DFSs provide better image quality and IQI visibility than do industrial X ray films In a high contrast sensitivity mode the DDAs achieve significantly better IQI readings than do film exposures This effect is observed when sub pixel contrast resolution is achieved This is the case if the SNR at the detector is increased considerably If a wire or crack is smaller than a pixel it still influences the contrast and can be seen in the image if the contrast is sufficiently higher than the noise Therefore systems with insufficient spatial resolution can be applied if their high unsharpness 1s compensated for by an increased SNR The improved SNR of the DDA allows wire W19 50 um diameter to be detected at a detector pixel size of 200 um without a magnification technique It is proposed to permit the application of unsharp systems if the visibility of the required wire or s
111. tif Fe5mm 220kV 8mA 700mm 200ms 60s tif A 5 mm thick steel plate was used for calibration Besides the dark image four white images were generated for calibration of the full dynamic range With 8 mA at a 700 mm distance no detector saturation was obtained The other darker images should have grey values linearly increasing from the darkest to the brightest image It is useful to have at least double the integration time for detector calibration as used later for image acquisition If the source to detector distance changes some artefacts in the detector calibration will appear because of the changes in X ray source shading overlying the internal detector shading mainly from objective In Fig 17 the improvement of image quality is shown before and after calibration for an Inconel step wedge Of course during acquisition of images for fluoroscope calibration the calibration function in V2 has to be deactivated e g no source calibration text file as in Fig 16 Exposure conditions are given in the displayed file name 3 3 QUALIFICATION PROCEDURES FOR FLUOROSCOPE QUALIFICATION USING ISEE ACCORDING TO ASTM E 2597 Procedures for image processing and data evaluation using ISee version 1 10 are described in detail in the user manual This manual with procedures and examples for image processing is available at http www kb bam de ic 22 The purpose of the following guidelines is to demonstrate and to assist in the application of the
112. ting the film and different chemicals thus giving birth to computed radiography An imaging plate consists of a flexible polymer support coated with a sensitive layer On top it is covered with a thin transparent protective layer The sensitive layer of the most common systems consists of a mixture of BaFBr crystallites doped with europium and a binder X ray or gamma ray quanta result in activation of F centres in the crystallites which result in the emission of blue light photons upon stimulation with red light photons through a process known as photo stimulated luminescence see Fig 2 After X ray exposure imaging plates have to be scanned by a laser scanner to obtain a digital image radiograph Finally the residual information stored in the F centres can be erased by exposure to bright white light and the imaging plate can be reused up to 1000 times Different plate systems are commercially available with different thickness unsharpness and sensitivity Guidelines and standards that define good workmanship criteria for new digital detectors have been developed and remain under revision aimed at avoiding a loss of information and reduced probability of flaw detection which may occur by adoption of medical systems without adaptation to NDT requirements Storage 4 Phosphor Imaging Plate FIG 2 Principle of computed radiography with imaging plates 1 2 5 Digital detector arrays or flat panel detectors 1 2 5 1 Indirect X ray imaging
113. ting it on the opposite side Fig 1 Object Fir X ray source FIG 1 Typical set up for radiographic inspection with films RT still represents the largest NDT method on the market At present the amount of industrial NDT carried out using radiographic film sandwiched between lead intensifying screens as a detector is continuing to increase around the world largely for the following reasons RT is technically superior in detection ability for internal defects in many situations e g inspection of complicated shapes and where non contact techniques are required RT is the only option for the majority of in line factory production line testing e g in line testing of castings electronic components such as printed circuit boards and food products Here any interruption of the process is unacceptable and RT is the only testing method that can satisfy this constraint RT can detect defects in structures where direct access is not possible e g pipelines and other structures covered with thick paint or insulation or having a rough surface finish Here other NDT methods require considerable preparation effort and time RT shows good detection ability for defects in multi layered structures austenitic steels and composites where other NDT methods such as ultrasonic testing cannot be used due to attenuation and scattering problems Results of inspections are easy to interpret The ability of this source specimen film
114. vealed new potential for accurate evaluation of defects by radiation techniques To review the new developments in digital industrial radiography DIR and to recognize the significant potential of DIR techniques in the life assessment and extension of components facilities and products a meeting of experts was convened at the IAEA in November 2005 Based on the results of this meeting the IAEA conducted several regional training courses in which participants from Member States were given training in DIR techniques The IAEA also supported establishing facilities for DIR techniques in some Member States Realizing the need for easy construction and assembly of a low cost more economically viable system for DIR technology the IAEA conducted a coordinated research project CRP during 2007 2010 for research and development in the field of digital radiology with the participation of 12 Member State laboratories The current publication on design development and optimization of a low cost DIR system is based on the findings of this CRP and inputs from other experts The report provides guidelines to enable interested Member States to build their own DIR system in an affordable manner The IAEA wishes to thank the authors and CRP participants who contributed to this report In particular the IAEA is grateful to U Ewert and U Zscherpel Federal Institute for Materials Research and Testing Germany for their valuable contributions and guidance during th
115. work on some computers only 32 bit drivers available FireWire connectors and adapters are not readily available in some countries Wrong exposure conditions measurements of quantitative parameters IQI values etc 14 Solution Use black matt painting inside the fluoroscope box along with firm and light tight assembly Use masking and collimation of the X ray beam Turn aperture of the objective to maximum Adjust brightness to obtain grey value between 2 and 10 for no radiation Adjust shutter exposure time per frame to have a high grey value for the thinnest part of the specimen to be inspected just below the red warning colour in the V2 window Try another tube with constant potential generator Use digital temporal filter in V2 software Assemble the housing strictly according to BAM drawings Field of view should be 100 mm x 150 mm To increase or decrease field of view change the optical system dimensions magnification etc Use Duplex Wire IQI according to ISO 19232 5 ASTM E2002 or EN 462 5 and one of the following Single Wire IQI according to ISO 19232 1 and EN 462 1 or ASTM E 747 Plate Hole Penetrameter according to ASTM E1025 Step Hole IQI according to EN 462 2 Use compensation principle for IQI sensitivity measurement as described in ISO DIS 17636 2 Follow the requirements for minimal SNR values and exposure time as specified in ISO DIS 17636 2 Increase exposure time if wire IQI readout is to
116. ww kb bam de alex v2 index html Select proper number of frames to be averaged frame integration number 50 500 is suggested It should be high enough to meet the required minimum SNR value Frame integration number for calibration must be two to four times the frame number used for acquisition Follow the calibration procedure http www kb bam de alex ic calibration correction index html Problems with image acquisition and fluoroscope calibration 2 5 COST ANALYSIS OF VARIOUS DIGITAL INDUSTRIAL RADIOLOGY SYSTEMS The construction of the digital fluoroscopic system DFS consists of two parts 1 e the casing housing and shielding and the optical components Table 3 lists the components of the digital fluoroscope These were directly purchased and provided by the IAEA at a total cost of 2882 per DFS Table 5 shows the cost of DIR systems of different Member States For the fabrication of the DFS casing the cost ranges between 1900 and 3000 depending on the manufacturing costs in the Member States The software developed by BAM was used and the other hardware items listed in the table were provided by the IAEA at a total cost of 2882 per DFS Therefore the total cost to fabricate the complete DFS was observed to range between about 4800 and 5900 without taking into consideration the cost of the computer and the shipping and transportation costs The prices indicated exclude taxes and overhead It can be observed that the
117. y the magnification Digital detectors are typically characterized by their detector pitch also called the pixel size which 1s equivalent to the distance between the centres of two neighbouring detector elements To consider in addition unsharpness contributions by the sensitive detection layer of imaging plates CR scanners and DDAs the concept of the basic spatial resolution SR in um was introduced which corresponds to an effective pixel size Whereas the pixel size is determined by the construction or software settings e g within CR scanners the SR can be measured in the image in a number of ways The most convenient and recommended method is to use the duplex wire method see the IQI description in EN 462 5 ASTM E 2002 or ISO 19232 5 The measurement with the duplex wire IQI provides a total unsharpness value u in um which is equivalent to the spatial resolution The basic spatial resolution SR is calculated by SR u 2 12 1 3 3 4 Specific material thickness range Considering the practical aspects of radiographic applications an additional parameter used is the specific material thickness range SMTR which means the extent of material thicknesses covered in the same image without detector saturation and ensuring a minimum SNR in the image Since this value is low for NDT film systems limited by the usable optical density range of 2 4 5 corresponding to a radiation intensity ratio of only 3 it usually is not cons

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