Line Filtering (T31) - Intrepid Geophysics
Contents
1. Parameter Unit Default value Nominal Level of Survey m Number of Bins to Sort Heights Nominal Height of Bin m Cutoff Weight 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Downward Continuation filter If you choose the Downward Continuation filter INTREPID displays the Downward Library Help Top Continuation Filter Properties dialog box Downward Continuation Filter Properties Downward Continuation Filter Properties Filter Name Filter Space FOURIER Filter Properties Level of continuation 100 in metres No of Weight control points Extend D ata Using Zero Pad Mirror Pad Data Flipped Mirror Pad Data Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Window Size 16 points Edit the parameter as required and choose OK Line Filtering T31 31 lt 4 Back gt See Continuation filters reference in INTREPID spectral domain operations reference R14 and specifically Downward Continuation filter reference in INTREPID spectral domain operations reference R14 for information about this filter Downward Continuation filter Parameters Parameter Unit Default value Level of Continuation m 100 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Vertical Horizontal Component filter Library2. Order of differentiation To No of Weight Control Points ny Zero Pad Mirror Pad Data Flipped Mirror Pad Data Extend D ata Using Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Window Size points Accept Cancel Edit the parameters as required and choose OK Note You can specify a fractional vertical derivative For example if you have noisy data you may obtain better results using the 0 85 vertical derivative See Vertical derivative filter including fractional vertical derivative reference in INTREPID spectral domain operations reference R14 for information about this filter Vertical Derivative filter parameters Parameter Unit Default value Order of Differentiation 1 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 29 Library Help Top lt 4 Back gt Horizontal Derivative filter gradient filters If you choose Horizontal Derivative INTREPID displays the Horizontal Derivative Properties dialog box Horizontal Derivative Filter Properties Horizontal Derivative Filter Properties Filter Name HorizontalDerivate Untitled Filter Space FOURIER Filter Properties No of Weight Control Points 2 aaaea amaan Extend D ata U sing Zero Pad Mirror Pad Data Flipped Mirror Pad Data Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Wi
3. 2012 Intrepid Geophysics lt 4 Back gt
4. 3 Choose Save Options from the File menu Specify a task specification file INTREPID will add the extension job INTREPID will create the file with the settings current at the time of the Save Options operation For full instructions on creating and editing task specification files see INTREPID task specification job files R06 gt gt To use a task specification file for a batch mode Line Filter task Type the command nlinefilter exe with the switch batch followed by the name and path if necessary of the task specification file For example if you had a task specification file called surv329 job in the current directory you would use the command nlinefilter exe batch surv329 job 2012 Intrepid Geophysics lt 4 Back gt Line Filtering T31 36 INTREPID User Manual lt 4 Back gt Library Help Top Task specification file notes and example Here is an example of a Line Filter task specification file Process Begin Name linefilter Parameters Begin InputFilters Begin InputFilter UpwardContinuation Untitled InputFilters End LineIO Begin InputLines diskl survey67 ebagoola_s InputZField disk1 survey67 ebagoola_S raw_mag OutputZField disk1 survey67 ebagoola_S upward LineIO End ProcessParameters Begin Process ALL_LINES StartLineNumber 2731 EndLineNumber 7122 NoOfLines 36 SampleMode XY_BASED ProcessParameters End Parameters End Process End Library Help Top
5. Help Top Line Filtering T31 32 lt 4 Back gt If you choose the Vertical or Horizontal Component filter INTREPID displays the corresponding filter properties dialog box Reduction to the Pole Filter Properties VERTCOMP Filter Properties Filter Name VerticalComponent Untitled Filter Space FOURIER Filter Properties No of Weight Control Points h2 Calculated Reference Field Date z Sensor Height 0 in kms Calculate Lat Long from Line Data O Stsr Reference Field choices C AGRF IGRF C MANUAL Manual Reference Field choices Field Strength a SEn Field Inclination oo ee Extend D ata U sing C Zero Pad Mirror Pad Data C Flipped Mirror Pad Data Roll Off Using C Bartlett Window Hanning Window C Parzen Window Roll Off Window Size points Accept Cancel Reduction to the Pole Filter Properties HORIZCOMP Filter Properties Filter Name HorizontalComponent Untitled Filter Space FOURIER Filter Properties No of Weight Control Points h2 Calculated Reference Field Date 1 nu Sensor Height in kms Calculate Lat Long from Line Data Latitude ed Longitude 0 Reference Field choices C AGRF IGRF C MANUAL Manual Reference Field choices Field Strength Field Declination oo Field Inclination oo Extend D ata U sing C Zero Pad Mirror Pad Data C Flipped Mirror Pad Dat
6. 0 589 Sample Spacing 0 05817 in kms Nyquist Frequency 8 5961174 in cycles km Interpolation Method Linear C Cubic Spline C Nearest Neighbour Average Line Direction North to top Display Options M Detrend Displayed Line M Overlay Filtered line l Zoom Both Lines OK Cancel 1 Right button click the line display INTREPID displays the Current Line Statistics and Options dialog box Note this is a Tensor example display 2 View the statistics and select options as required then choose Accept No of Samples The number of data points in the current line that have values for the current Z field No of Interpolated Samples The number of data points in the current line derived by resampling and used for the line filter calculations Maximum Z Value Minimum Z Value Mean Z Value Z Values Standard Deviation INTREPID displays basic statistics for the current line Sample Spacing Spatial resampling only This parameter corresponds to the distance between interpolated samples You can modify this to increase or decrease the resampling rate and thus the Nyquist frequency Nyquist Frequency The highest frequency possible in the spectral domain given the current resampling rate 1 6 In the current version of INTREPID this statistic is provided by a revised general reporting class See Resampling mode for further details Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filteri
7. C Zero Pad Mirror Pad Data C Flipped Mirror Pad Data C Bartlett Window Hanning Window C Parzen Window 16 Replace trend in Output Accept Cancel Edit the parameters as required and choose Accept Line Filtering T31 25 4 Back gt See Low pass filter reference in INTREPID spectral domain operations reference R14 for information about this filter Low Pass filter parameters Parameter Unit Unit Spatial Default Chronological value Low Cutoff Frequency cycles 1000 fids cycles km 25 Cutoff Rolloff Parameter cycles 1000 fids cycles km 5 Replace trend in output Yes 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top High Pass filter If you choose High Pass INTREPID displays the High Pass Filter Properties dialog Library Help Top box High Pass Filter Properties High Pass Filter Properties Filter Name High Pass Untitled SS Filter Space FOURIER Filter Properties eo a a M Cut Off Roll Off Parameter C cycles km No of Weight Control Points Extend D ata U sing Zero Pad Mirror Pad Data Flipped Mirror Pad Data Bartlett Window Hanning Window Parzen Window Roll Off Window Size Accept Cancel Edit the parameters as required and choose Accept Line Filtering T31 26 lt 4 Back gt See High pass filter reference in INTREPID spectral domain operations refer
8. and drag to the diagonally opposite corner of the region INTREPID displays a frame defining the region you select 2 Release the mouse button INTREPID will enlarge the display to show only those points you selected Intrepid Linefilter Tool 3 2beta8 Line 2742 _Z Dataset raw_mag T T CERN A CAN _ Goto Power Spectrum coat Line Jos In this illustration the INTREPID has not synchronised the profiles gt gt To zoom out Double click anywhere in the zoomed display with the left mouse button Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 9 Library Help Top lt 4 Back gt Line Filter display options Querying lines and setting line options You can display information about the current line and select a range of options for processing it as described in this section gt gt To query the current line and select options Hines 0 sSenal iieleoieta Sensory Beanie ad sai Line Statistics No of Samples 215 No of Interpolated Samples 215 Field Minimum Maximum Mean StdDev Nulls Declination Inclination Dispersion Ev1 15 1435002703 108 599591926 42 1595469646 16 3904 0 66 694 13 928 51 612 Ev2 39 3167952196 47 9755198932 4 03505362159 13 8897 29 371 5579 51 974 EV3 147 176184338 12 4719121487 46 1946005861 18 6695 12 824 80 127 44 517 Mean Trace 7 1054273576e 015 EigenVector Volume
9. cycles km Cut Off Roll Off Parameter a cycles km No of Weight Control Points B el Extend D ata U sing Zero Pad Mirror Pad Data Flipped Mirror Pad Data Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Window Size Accept Cancel Edit the parameters as required and choose Accept See Band pass filter reference in INTREPID spectral domain operations reference R14 for information about this filter Band Pass and Band Reject filter parameters Parameter Unit Chronological Unit Spatial Default value Low Cutoff Frequency cycles 1000 fids cycles km 10 Low Cutoff Rolloff Parameter cycles 1000 fids cycles km 5 High Cutoff Frequency cycles 1000 fids cycles km 25 High Cutoff Rolloff Parameter cycles 1000 fids cycles km 5 Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Low Pass filter If you choose Low Pass INTREPID displays the Low Pass Filter Properties dialog Library Help Top box Low Pass Filter Properties Low Pass Filter Properties Filter Name Filter Space Filter Properties Low Pass Cut Off Frequency 25 in cycles km Cut Off Roll Off Parameter 5 No of Weight Control Points Extend D ata Using Roll Off Using Roll Off Window Size LowPass Untitled FOURIER in cycles km
10. viewing it For further information about power spectrum graphs see Power spectrum graphs in INTREPID spectral domain operations reference R14 Library Help Top 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 12 Library Help Top 4 Back gt Filter operations Overview You can perform the following operations with filters for the current dataset and Z field Specify a new filter which can be One of the standard filters supplied with INTREPID A filter specified by you using a profile with control points A composite filter consisting of two or more standard and or user defined filters Load a filter definition file in order to specify a new filter View and modify if required the current filter parameters View and edit if required the user defined filter if it exists Save the current filter definition to a filter definition file for later reference or use View the Power Spectrum graph for the current filter Overlay the current filter profile on the original Z field profile Apply the filter to the dataset and save the results in a Z field if required You can perform all but three of these operations using options from the Filter menu For viewing the power spectrum graph see Power Spectrum display For overlaying the display see Overlaying the filter results For applying the filter and saving the results see Applying the current filter a
11. INTREPID User Manual Line Filtering T31 1 Library Help Top 4 Back gt Line Filtering T31 Top The INTREPID Line Filter tool provides a comprehensive range of spatial and spectral domain filters for applying to line datasets Using the Line Filter tool you can Display profiles of individual lines from a line dataset Configure and apply to the line data Single filters selected from a comprehensive range of standard spatial and spectral domain filters Filters defined by you using a filter profile Filters previously defined and saved in filter definition files Composite filters consisting of a number of saved filter definitions INTREPID applies these serially to the data View a power spectrum graph for the current filter results for any line Before applying the filters to the data and saving the results you can view profiles of individual lines showing the original data and the filtered results Fourier amp Spatial filter Tensor Quaternion amp Vector Fields BETA Using the Line Filter tool gt gt To use Line Filter with the INTREPID graphic user interface 1 Library Help Top Choose Line filter from the Filter menu in the Project Manager or use the command 1filter exe INTREPID displays the Line Filter Main window Intrepid Line Filter v4 1 Release Build 125 0 x File Spatial Spectral Special Help iif If you have previously prepared file specifications and par
12. Library Help Top 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 22 Library Help Top lt 4 Back gt Information about spatial domain filters Library Help Top The Line Filter tool uses the standard dialog box for each filter See the corresponding sections in INTREPID spatial and time domain filters and transformations R13 for details about the filters e User defined convolution kernels in INTREPID spatial and time domain filters and transformations R13 Local mean median filters in INTREPID spatial and time domain filters and transformations R13 Fuller filter in INTREPID spatial and time domain filters and transformations R13 Naudy filter in INTREPID spatial and time domain filters and transformations R13 e Automatic gain control filter for line data in INTREPID spatial and time domain filters and transformations R13 Hilbert transform in INTREPID spatial and time domain filters and transformations R13 Phillips automatic depth estimation in INTREPID spatial and time domain filters and transformations R18 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Library Help Top Standard spectral domain filters Library Help Top Line Filtering T31 23 lt 4 Back gt INTREPID includes the following spectral domain standard filters for your use You can use the filters mar
13. NTREPID will process the dataset as specified Applying composite filters If the current filter is a composite filter either loaded from a single filter definition file or composed by you in this session INTREPID will Apply the first component to the input data 2 Apply the second and subsequent filters to the results of the immediately preceding filters 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 19 Library Help Top 4 Back gt Creating the extended region for filters To prevent loss of data at line ends line filters use an extended region at each end of the line where values of the first or last original data point can be rolled off to zero The properties dialog boxes of these filters contain parameters for specifying the extended region Extend D ata U sing O Zero Pad Mirror Pad Data Flipped Mirror Pad Data Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Window Size 16 points For spectral domain filters you can specify the size of the extended region The extended region size for the Hilbert transform is half of the filter window length See Rolloff Window Size for detailed instructions INTREPID calculates initial Z values for the data points in the extended region These can be based on nearby original data values See Data extension method for instructions After calculating the extended region initial valu
14. Please contact our technical support service for further information Loading and saving filter definitions You can save filter definitions for use at a later time and maintain your own library of filter definitions for loading into the Line Filter tool Before specifying a composite filter you must save the definitions of the component filters See Specifying composite filters for details Filter definition files INTREPID stores filter definitions as block structured auxiliary files with FilterDescription Begin FilterDescription End blocks See INTREPID Auxiliary files in INTREPID database file and data structures R05 for general details about auxiliary files Filter definition files have the extension fdf and normally reside in the directory install_path filters Filter definitions to be used in creating a composite filter must reside in this directory A filter definition file may contain a number of filter definitions Each will have its own FilterDescription Begin FilterDescription End block Here is a sample filter definition file FilterDescription Begin Name UpwardContinuation Survey67 Space FOURIER Type INTRINSIC IntrinsicType UPCONTINUATION UpwardContinuation Begin Level 100 000000 DataWindowType HANNING DataPadType MIRROR_PAD RolloffWindowSize 16 UpwardContinuation End FilterDescription End Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filte
15. a Roll Off Using C Bartlett Window Hanning Window C Parzen Window Roll Off Window Size points Accept Cancel Edit the parameters as required and choose OK You can specify the Earth s core magnetic field data manually or have INTREPID calculate it for you using the AGRF or IGRF See Horizontal and vertical components filters reference in INTREPID spectral domain operations reference R14 for information about this filter 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Library Help Top Vertical Horizontal Component filter Parameters Line Filtering T31 33 4 Back gt Parameter Unit Default value Reference Field Date dd mm yy 1180 Sensor height m 0 Calculate Latitude and Longitude from line data Yes Latitude 7 0 Longitude S 0 Reference Field AGRF IGRF Manual AGRF Manual Field Strength Z units nT 0 Manual Field Declination j 0 Manual Field Inclination z 0 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Line Filtering T31 34 lt 4 Back gt Special filters INTREPID includes the following special purpose filters for your use Phillips Depth Gravity Inversion Strip Gravity Layer e Pass through Select the filter you want from the list under the Special New Special option Phillips Depth filter If you choose the Phillips D
16. ameter settings for Line Filter load the corresponding task specification file using Load Options from the File menu See Specifying input and output files for detailed instructions If all of the specifications are correct in this file go to step 6 If you wish to modify any settings carry out the following steps as required 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Line Filtering T31 2 lt 4 Back gt 3 Specify the dataset for the Line Filter Use Load Lines from the File menu See Specifying input and output files for detailed instructions INTREPID displays the dataset in the Line Filter window Intrepid Linefilter Tool 3 2beta8 Line 2742 _Z Dataset raw_maq T T T T fe 4 5 E T soto i i Filtered Line Display i 4 Specify the filter you require for the dataset See Filter operations for detailed instructions INTREPID displays the filter for the current line Intrepid Linefilter Tool 3 2beta8 Line 2742 _Z Dataset raw_mag T T T fe 0 fe hi Power Spectrum lt lt Previous T 5 Navigate the dataset select display options and adjust the filter specifications as required See Navigating the profile display Line Filter display options and Filter operations for detailed instructions 6 If you wish to view filter results for some or all of the dataset use Process
17. ch standard filter properties dialog box contains a Filter Name text box When you first specify a new filter it shows the type of filter with the notation Untitled If you save the current settings for the current standard filter you specify the name of the saved filter specifications in the Filter Name text box INTREPID uses this file name when storing it See Loading and saving filter definitions for details If you load an existing set of standard filter specifications INTREPID will identify it using the name in the text box See Loading and saving filter definitions for details Library Help Top 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 14 Library Help Top lt 4 Back gt Specifying user defined filters New user defined filters The user defined filters facility will be available in INTREPID shortly Please contact our technical support service for further information File New Filter g Standard Edit Current Filter Composite aaa Taw_mi Current Filter Properties Ea B imma Fourier Spatial 4 Load Filter Save Filter Choose Fourier or Spatial from the User Defined cascade in New Filter in the Filter menu The Line Filter tool actually uses the Hartley algorithm for the spectral transform Fourier is used here in a generic sense Editing a user defined filter The user defined filters facility will be available in INTREPID shortly
18. ct the option corresponding to your line selection method Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 18 Library Help Top Library Help Top 4 Back gt Select from List Select a Range Select a Line Select All 4 Ifyou selected Select from List Move the line numbers between the Dataset Line Numbers and Selected Line Numbers list boxes as required The Selected Line Numbers list box shows a list of the lines for processing and the Dataset Line Numbers list box shows a list of lines that are not for processing To move a line number to the other list select click it so that it is highlighted then choose gt gt Add gt gt or lt lt Remove lt lt If you selected Select a Range enter the first and last line numbers to be processed into the corresponding text boxes If you selected Select a Line enter the number of the line required in the corresponding text box Note For Select a Range and Select a Line you can enter line numbers or the words start and end which signify the first and last line numbers When you have specified the lines for processing choose Accept If you chose Save Displayed Z Trace As from the File menu INTREPID displays a Save As dialog box for you to specify the field name for the filter results Specify the field and choose OK See Specifying input and output files for further details about file operations 7 I
19. d saved all of the required component filters in the install_path filters directory See Loading and saving filter definitions for instructions 2 Choose Composite from the New Filter cascade in the Filter menu INTREPID displays the Filter Builder dialog box Milter Duilder Pre detined Hikers Compas ite Filter Add gt in_va MAGgG Edit Filter lt lt Remove lt Ok Cancel The Filter Builder dialog box contains two list boxes The Predefined Filters list box contains the names of the filter definitions in the directory install_path filters The Composite Filter list box contains the names of the filters you have selected for the composite filter 3 Select the filter definitions to be used by moving their names to the Composite Filter list To select a filter as a component select click its name in the Predefined Filters list so that it is highlighted then choose gt gt so that it appears in the Composite Filter list To remove a filter from the composite filter select click its name in the Composite Filter list so that it is highlighted then choose lt lt to remove it and place it back in the Predefined Filters list 4 When you have finished selecting the component filters choose OK The composite filter will become the current filter replacing the previous current filter specification Tip If you intend to save the composite filter do so promptly before you inadvertently e
20. edit aliases Line Filtering T31 6 4 Back gt 1 Choose Edit Dataset Aliases from the Resampling Mode dialog box 2 INTREPID may display an Open dialog box for a vector dataset If it does select the current dataset 3 INTREPID displays the Dataset Alias Editor Edit Aliases ___LineType__ FlightNumber line linetype fid NONE NONE This editor works in the same way as the one displayed by the Project Manager See Editing the dataset aliases in INTREPID Old Project Manager T01 for instructions Navigating the profile display Library Help Top The Line Filter window shows two profiles of a single line from the dataset the current line These profiles are The original Z field and The results of filters currently specified Normally the horizontal scales of the Z field and filter results are synchronised so that you can compare corresponding values for any data point File Filter Intrepid Linefilter Tool 3 2beta8 Line 2742 _Z Dataset raw_mag in er Power Spectrum lt lt Previous Filtered Line Bi 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 7 Library Help Top lt 4 Back gt You can navigate the dataset display in the following ways Viewing the profile of any line in the dataset Zooming in on any section of a profile Selecting a line you wish to vi
21. ence R14 for information about this filter High Pass filter parameters Parameter Unit Unit Spatial Default Chronological value High Cutoff Frequency cycles 1000 fids cycles km 5 Cutoff Rolloff Parameter cycles 1000 fids cycles km 5 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 27 Library Help Top 4 Back gt Reduction to the Pole filter Library Help Top Reduction to the Pole Filter Properties REDTOPOLE Filter Properties ReductionToPole Untitled Filter Name Filter Space FOURIER Filter Properties No of Weight Control Points 12 Calculated Reference Field Date 1 a 7 80 Sensor Heim in kms W Calculate Lat Long from Line Data Latitude 0 Longitude Reference Field choices C AGRF IGRF C MANUAL Manual Reference Field choices Field Strength Field Declination joo Field Inclination _ 0 0 OOOO Extend D ata U sing C Zero Pad Mirror Pad Data C Flipped Mirror Pad Data Roll Off Using C Bartlett Window Hanning Window C Parzen Window Roll Off Window Size 16 points Accept Cancel North South oriented acquisition lines only If you choose Reduction to the Pole INTREPID displays the Reduction to the Pole Filter Properties dialog box Edit the parameters as required and choose OK Y
22. epth filter INTREPID displays the Phillips Auto Depth Filter Properties dialog box Edit the parameters as required and choose OK See Phillips automatic depth estimation in INTREPID spatial and time domain filters and transformations R13 Gravity Inversion filter Exit Library Help Top If you choose the Gravity Inversion filter INTREPID displays the Gravity Inversion Filter Properties dialog box Edit the parameters as required and choose OK See Phillips automatic depth estimation in INTREPID spatial and time domain filters and transformations R13 To exit from Line Filter choose Quit from the file menu 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 35 Library Help Top lt 4 Back gt Displaying options and using task specification files Displaying options See Querying lines and setting line options for information about displaying the pre filter settings for the current line See Viewing and modifying the current standard filter properties for information about displaying the filter settings Using task specification files Library Help Top You can store sets of file specifications and parameter settings for Line Filter in task specification job files gt gt To create a task specification file with the Line Filter tool 1 Specify all files and parameters 2 If possible execute the task choose Apply to ensure that it will work
23. es INTREPID applies a rolloff process so that the values at the end of the extended region have a smooth transition to zero See Edge damping methods for instructions For further information about data extension for spectral domain filters see Preparation of data for spectral transform in INTREPID spectral domain operations reference R14 Rolloff Window Size Spectral domain filters Use the text box to specify the number of data points in the extended region We recommend that this number is a power of 2 Hilbert Transform INTREPID automatically calculates the length of the extended region See Extended region size in INTREPID spatial and time domain filters and transformations R18 for details Data extension method Library Help Top INTREPID has three options for extended region values as described below In the dialog box for the filter select the Data Extension Method option as required Zero Pad INTREPID sets all extended region values to zero Mirror Pad Data INTREPID extrapolates values so that the profile of the extended region Z values is a Y reflection of the profile of the Z values of the same number of original data points at that end of the line This is the default option for spectral domain filters Flipped Mirror Pad Data INTREPID extrapolates values so that the profile of the extended region Z values is a Y reflection then an X reflection of the profile of the Z values of the same number of origi
24. ew When you first load a line dataset INTREPID displays Z data from the first line in the dataset You can display other lines using the Next Previous and Go To command buttons The Line Filter automatically sorts line numbers into ascending order no irrespective of their actual order in the dataset gt gt To view the Next or Previous line according to line number Use Next or Previous from the Line Filter window to view the next or previous line respectively gt gt To view the line of your choice Select Line 1 Choose Go To in the Line Filter window INTREPID displays the Select Line dialog box 2 Select click the number of the line you wish to view then choose OK INTREPID displays the line Enlarging and reducing zooming the profile display You can enlarge the profile display zoom in to display only part of a line profile then zoom out again when you have finished You can specify whether both profiles will remain synchronised when you perform zoom operations Normally INTREPID synchronises the profiles See Querying lines and setting line options for instructions about turning synchronisation on and off Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 8 Library Help Top lt 4 Back gt gt gt To zoom in on a set of data points 1 Move the mouse pointer to one corner of the region that you wish to enlarge Hold down the left button
25. from the Line Filter window If you wish to save the filter results into a dataset field as well use Save Displayed Z Trace As from the File menu instead See Applying the current filter and saving the filter results for detailed instructions 7 Ifyou wish to record the specifications for this process in a job file in order to repeat a similar task later or for some other reason use Save Options from the file menu See Specifying input and output files for detailed instructions Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 3 Library Help Top 4 Back gt 8 Ifyou wish to repeat the process repeat steps 4 7 using the same dataset and Z field or 2 7 using a different dataset varying the specifications as required 9 To exit from Line Filter choose Quit from the File menu You can execute Line Filter as a batch task using a task specification job file that you have previously prepared See Displaying options and using task specification files for details Specifying input and output files To use Line Filter you will need to specify the line dataset to be loaded and the Z field to be processed When you have specified the filter s to be used you may wish to specify a new Z field for saving the filter results You can also load and save filter specifications See Loading and saving filter definitions Choose the options as required from the Fi
26. ilter definitions for instructions Resampling mode The Line Filter tool requires data points in the line dataset to be evenly distributed with no internal gaps When INTREPID loads a line dataset it immediately resamples it so that this is the case INTREPID replaces nulls using the cubic spline linear or nearest neighbour interpolation method The default method is linear interpolation You can change the method using the Current Line Statistics and Options dialog box See Querying lines and setting line options for instructions You can select one of three resampling modes For two of these modes you need aliases as described below Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 5 Library Help Top lt 4 Back gt gt gt To select the resampling mode 1 Load a line dataset for filtering as described above INTREPID displays the Resampling Mode dialog box Sample Mode Select S ample Parameterization Mode Geo Located requires XY Lines C Time Based requires a FID line C Fixed Increment enetered below Sample Increment 1 0 Edit Survey Info Ok Cancel 2 Select the resampling mode as required then choose Accept Spatial Geo Located INTREPID examines the X and Y fields of the dataset and resamples the data so that it is distributed evenly with respect to distance If you choose this option your line dataset must have prope
27. ked with full tensor datasets Band Pass Band Reject Low Pass High Pass e Vertical Derivative e Horizontal Derivative Upward Continuation Downward Continuation e Variable Continuation Reduction to the Pole Vertical Component Horizontal Component e Fourier Hilbert Select the filter you want from the list under the Spectral New Fourier option For more complex signal fields just Band Pass Reject Low amp High pass are supported in the V4 1 implementation New Filter Intrinsic AGC Edit Current Filter Composite Band Pass Current Filter Properties User Defined Band Reject Load Filter Low Pass Save Filter High Pass Reduction To Pole Vertical Derivative Horizontal Derivate Upward Continuation Downward Continuation Vertical Component Horizontal Component Hilbert Naudy Fuller Convolution Filter4 No Filter following sections 2012 Intrepid Geophysics INTREPID displays the standard filter properties dialog box as described in the 4 Back gt INTREPID User Manual Library Help Top Key to notations in this section Line Filtering T31 24 lt 4 Back gt Unit Spatial The unit for a parameter if you are using Spatial resampling mode for the dataset See Resampling mode Unit Chronological The unit for a parameter if you are using Chronological resampling mode for the dataset See Resampling mode Fids Fid
28. le Continuation filter INTREPID displays the Variable Continuation Filter Properties dialog box Variable Continuation Filter Properties Variable Continuation Filter Properties Filter Name VariableContinuation Untitled Filter Space Filter Properties Sensor Altitude m C Continue Signal to Drape Altitude field m Continue signal to a constant sensor Altitude m Defaults to mean Altitude 370 00 Signal processing Do not split into elevation bins slower Split into elevation bins faster Number of bins to sort heights must be odd Nominal height of bins in meter Stabilization parameter for downward continuation C Do not stabilize downward continuation Stabilize if filter weights are larger than Low pass Butterworth filter order Extend Data Using Roll Off Using FOURIER ALTITUDE DRAPESURFACE_FOURIER 50 00 C ist 2nd 3rd 4th C Zero Pad Mirror Pad Data C Flipped Mirror Pad Data C Bartlett Window Hanning Window C Parzen Window Roll Off Window Size points V Replace trend in Output Cancel See Continuation filters reference in INTREPID spectral domain operations reference R14 and specifically Variable continuation filter reference in INTREPID spectral domain operations reference R14 for information about this filter Variable continuation filter parameters
29. le menu The illustrations below show the file menu before and after loading a line dataset Gem Filter Filter Load Line Dataset Load Line Dataset m Save Filtered Z Trace As Load Options Save Options Load Options Save Options Quit Quit In each case INTREPID displays an Open or Save As dialog box Use the directory and file selector to locate the file you require See Specifying input and output files in Introduction to INTREPID R02 for information about specifying files INTREPID may need to obtain information from the dataset aliases If you select spatial or chronological resampling See Resampling mode the dataset must have aliases identifying appropriate field files Alias Field For spatial resampling X X coordinate location Y Y coordinate location For chronological resampling Fiducial Fiducial count See Editing aliases in Line Filtering T31 for more information about aliases 2012 Intrepid Geophysics 4 Back gt Library Help Top INTREPID User Manual Line Filtering T31 4 Library Help Top lt 4 Back gt Load Line Dataset Use this option to specify the line dataset for filtering INTREPID will prompt you to specify the line dataset the Signal field to be filtered and the resampling mode See Resampling mode If you have selected spatial resampling and there are no valid X and Y aliases specifyi
30. log box See Querying lines and setting line options for more information about this dialog box The illustration below shows a profile with filter overlay turned on Intrepid Linefilter Tool 3 2beta8 Line 2742 _Z Dataset raw_mag T T T er Spectrum Library Help Top 2012 Intrepid Geophysics lt 4 Back gt INTREPID User Manual Line Filtering T31 11 Library Help Top lt 4 Back gt Power Spectrum display If the current filter is a spectral domain filter you can display a power spectrum graph of the filter results for the current line The vertical axis represents energy spectral power The horizontal axis represents frequency in Cycles km if you have used spatial resampling to prepare the data for the Line Filter Hertz if you have used chronological sampling to prepare the data for the Line Filter See Resampling mode for information about spatial vs chronological resampling gt gt To display the spectral domain Power Spectrum graph for the current line when using spectral domain filters only 1 Ensure that the current filter is a spectral domain filter 2 Choose Power Spectrum from the Line Filter main window INTREPID displays the graph in a separate window Power Spectrum Display Log af Special Pats Vs Bergas ite spo itxY Serasi or in Hertz if FIDS used T T T Accept J Cancel Choose Accept to close the window when you have finished
31. nal data points at that end of the line This is the default option for spatial domain filters 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 20 Library Help Top 4 Back gt Edge damping methods Spectral domain filters INTREPID provides a choice of three edge damping methods for the extended region values Each of these modifies the initial values of the extended region so that they have a smooth transition to zero at the end of the extended region The available methods are Bartlett filter e Hanning the default method Parzen filter The filter dialog boxes have option buttons corresponding to these methods See Damping of dataset edges before spectral transform in INTREPID spectral domain operations reference R14 for further information about these rolloff methods Hilbert Transform automatically calculates the rolloff values in the extended region normally using the Flipped Mirror Pad data extension method Detrending and replacing trends Library Help Top Before applying most standard filters INTREPID detrends the data After applying the filter INTREPID will replace the trend if it makes sense to do so For some filters INTREPID includes an option in the properties dialog box enabling you to turn trend replacement on or off For further information about detrending see Detrending and replacing trends in INTREPID spatial and time domain filters a
32. nd saving the filter results Some filter concepts Filter windows Many of the processes performed on a line involve a window In order to process a target data point e g calculate a new value for it INTREPID examines a number of data points on either side of it The set of points involved in the process including the target point is called a window In most cases INTREPID processes a set of adjacent data points and often the whole line It will create a different window for each data point based on the neighbouring points In this way INTREPID passes a window across the data No of Weight Control Points When user defined filters are available in INTREPID their profile will be defined in terms of a number of coefficients corresponding to weigh control points in the profile Contact our technical support service for information about this topic if required INTREPID spatial and time domain filters and transformations For full details of spatial and time domain filters provided with INTREPID see INTREPID spatial and time domain filters and transformations R13 INTREPID spectral domain operations Library Help Top For full details of spectral domain operations and the spectral domain filters provided with INTREPID see INTREPID spectral domain operations reference R14 The Line Filter tool actually uses the Hartley algorithm for the spectral transform Fourier is used in this chapter in a generic sense 2012 Intre
33. nd transformations R13 and Detrending data values in INTREPID spectral domain operations reference R14 and Reproducing the trend in INTREPID spectral domain operations reference R14 INTREPID detrends using a weighted least squares fit on a line by line basis Future releases of INTREPID will have the option of removing a single dataset average trend from all lines 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 21 Library Help Top lt 4 Back gt Standard Spatial Domain filters INTREPID includes the following spatial domain standard filters for your use Convolution filter with user defined kernel available soon Local median Median Local mean Moving Average e Local maximum Naudy e Fuller e Automatic Gain Control AGC Lacoste RC Hilbert Transform Select the filter you want from the list under the Spatial New Convolution option File AGC n ee SETAN a E E Band Pass i urrent Filter Properties ser Define Band Reject Load Filter Low Pass o Save Filter High Pass Reduction To Pole Vertical Derivative Horizontal Derivate Upward Continuation Downward Continuation Vertical Component Horizontal Component Median 1000 2900 00 4900 it i ii Moving Average Naudy Filtete Fuller Phillips_Depth Convolution Filter4 os No Filter INTREPID displays the corresponding standard filter properties dialog box
34. ndow Size 16 points There are no specific parameters for the Horizontal Derivative filter Choose OK See Horizontal derivative line filter reference in INTREPID spectral domain operations reference R14 for information about this filter Upward Continuation filter If you choose the Upward Continuation filter INTREPID displays the Upward Continuation Filter Properties dialog box Upward Continuation Filter Properties Upward Continuation Filter Properties Filter Name UpwardContinuation Untitled Filter Space FOURIER Filter Properties Level of continuation in metres Extend D ata U sing Zero Pad Mirror Pad Data Flipped Mirror Pad Data Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Window Size 16 points Edit the parameter as required and choose OK See Continuation filters reference in INTREPID spectral domain operations reference R14 and specifically Upward Continuation filter reference in INTREPID spectral domain operations reference R14 for information about this filter Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Upward Continuation filter parameters Line Filtering T31 30 lt 4 Back gt Parameter Unit Default value Level of Continuation m 100 Variable continuation filter Library Help Top If you choose the Variab
35. ng T31 10 Library Help Top lt 4 Back gt Interpolation Method Use these options to specify Linear Cubic Spline Nearest Neighbour interpolation for the resampling process Cubic Spline interpolation uses a curve through a number of original data points on each side of the position for the resampled point Nearest neighbour uses the Z value of the nearest data point if the resampling is spatial or the preceding Z value if the resampling is chronological See Resampling mode for details Average Line Direction INTREPID displays the average bearing North towards the top as in a compass of the current line in this diagram Overlay Filtered Line If you turn on Overlay Filtered Line INTREPID displays the filter results in white both in their own display area and overlaid on the original Z data profile See Overlaying the filter results for details Zoom both lines If you turn on this option INTREPID will synchronise the horizontal axes of both profiles during zoom operations so you will be zooming on both lines simultaneously If you turn off this option INTREPID will only enlarge and reduce the profile you use to specify the zoom Overlaying the filter results INTREPID can display the filter results in white both in their own display area and overlaid on the original Z data profile gt gt To turn filter overlay display on or off Turn the Overlay Filtered Line on or off in the Current Line Statistics and Options dia
36. ng the location files INTREPID displays Open dialog boxes for you to specify them If you have selected chronological resampling and there is no valid Fiducial alias INTREPID displays an Open dialog box for you to specify it INTREPID will then open the dataset and display the profile of the first line in the Line Filter Main window Signal field extended to include Tensors Quaternions Vectors at V4 1 Save Displayed Signal Trace As Use this option to specify the name for the output Signal field containing the filter results If you have not applied the current filter to the required lines INTREPID will do this before saving the results See Applying the current filter and saving the filter results for details Load Options If you wish to use an existing task specification file to specify the Line Filter process use this option to specify the task specification file required INTREPID will load the file and use its contents to set all of the parameters for the Line Filter process See Specifying input and output files for more information Save Options If you wish to save the current Line Filter file specifications and parameter settings as an task specification file use this option to specify the filename and save the file See Displaying options and using task specification files for more information Load Filter Save Filter You can load and save filter specifications using options from the Filter menu See Loading and saving f
37. ou can specify the Earth s core magnetic field data manually or have INTREPID calculate it for you using the AGRF or IGRF Note The current version of INTREPID will produce correct results for North South oriented acquisition lines If you wish to use this filter with lines oriented in other directions please contact our technical support service See Reduction filters reference in INTREPID spectral domain operations reference R14 and specifically Reduction to the Pole reference in INTREPID spectral domain operations reference R14 for information about this filter 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top Reduction to the Pole filter parameters Line Filtering T31 28 4 Back gt Parameter Unit Default value Reference Field Date dd mm yy 1180 Sensor height m 0 Calculate Latitude and Longitude from line data Yes Latitude 0 Longitude 0 Reference Field AGRF IGRF Manual AGRF Manual Field Strength Z units 0 Manual Field Declination a 0 Manual Field Inclination 0 Vertical Derivative filter gradient filters Library Help Top If you choose Vertical Derivative INTREPID displays the Vertical Derivative Properties dialog box Vertical Derivative Filter Properties Vertical Derivative Filter Properties erticalDerivative Untitled Filter Name Filter Space FOURIER Filter Properties
38. pid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 13 Library Help Top lt 4 Back gt Specifying a new filter When you specify a new filter it will replace the existing filter specification You can create composite filters using saved filter definitions See Specifying composite filters for instructions Specifying standard filters New standard filters gt gt To specify a standard filter 1 Ensure that you have saved any existing filter definition as required See Loading and saving filter definitions for instructions 2 Choose the filter you require from the Standard cascade from New Filter in the Filter menu INTREPID displays the corresponding to the filter properties dialog box 3 Specify filter properties as required then choose Accept INTREPID displays the filter as specified for the current line and be ready to apply it to the dataset as required Viewing and modifying the current standard filter properties gt gt To view and modify if required the current standard filter properties 1 Choose Current Filter Properties from the Filters menu OR Right button click the Filtered Line Display profile INTREPID displays the properties dialog box for the current standard filter See Standard Spatial Domain filters and Standard spectral domain filters for details of the filter properties 2 View and modify if required the filter properties then choose Accept Standard filter names Ea
39. rase it by specifying a new filter Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 17 Library Help Top lt 4 Back gt Applying the current filter and saving the filter results After you have specified the filters for the Line Filter process you can apply them to some or all lines in the dataset You can apply the filter to a list of lines a range of lines a single line or all lines If you choose Save Displayed Z Trace As from the File menu INTREPID will apply the filters before saving the filter results as a Z field in the dataset Before applying the filters INTREPID enables you to select the lines for processing gt gt To apply the current filter to the dataset 1 Ensure that you have specified the filters according to your requirements 2 If you wish to calculate the filters but not necessarily save them choose Process from the Line Filter window If you wish to save the filter results as a field of the dataset choose Save Displayed Z Trace As from the File menu INTREPID displays the Lines to Filter dialog box Lines to Filter Input Directory D INTREPID tutorials data ebagoola_S Output Z field UNKNOWN Select from List Data Set Line Numbers gt gt Add gt gt Selected Line Numbers lt lt Remove lt lt Select A Range Select A Line Line Number Start Select All Lines Accept 3 Sele
40. ring T31 15 Library Help Top Library Help Top 4 Back p Saving filter definitions gt gt To save the current standard filter definition 1 2 Ensure that the current standard filter is specified as required for the definition Choose Save Filter from the Filters menu INTREPID displays the filter properties dialog box for the current standard filter Modify filter parameters if required Specify the name for the filter in the Filter Name text box then choose OK INTREPID will save the filter definition in the directory install_path filters Loading filter definitions gt gt To load a filter definition 1 Choose Load Filter from the Filters menu INTREPID displays an open dialog box with install_path filters as the current directory Specify the filter you require and choose OK INTREPID will load the filter definition and display the results in the Line Filter window 1 Before you do this the first time check that the directory exists and create it if necessary 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Line Filtering T31 16 Library Help Top lt 4 Back gt Specifying composite filters You can specify a composite filter using saved filter definitions After specifying a composite filter you can then save it as a filter definition for use in a later Line Filter session gt gt To specify a composite filter 1 Ensure that you have defined an
41. rly defined X and Y aliases Chronological Time Based INTREPID examines the fiducial field of the dataset and resamples the data so that it is distributed evenly with respect to time If you choose this option your line dataset must have a properly defined Fiducial alias Unlocated Fixed Increment INTREPID ignores any X Y and Fiducial data and assumes that the data points are already evenly distributed You can then specify a resampling interval for the data using some or all of it in the Line Filter process Resampling interval Sample Increment Use this text box to specify the resampling interval for Unlocated resampling mode INTREPID will use this to select data points for the line filtering process For example If you specify a resampling interval of 2 INTREPID will use every second data point for calculating the line filters If you specify a resampling interval of 5 INTREPID will include an interpolated data point between each pair of the original points for calculating the line filters Editing aliases While using the Resampling Mode dialog box you can edit the dataset aliases You may wish to do this in order to specify an X Y or Fiducial alias for use in this tool See Vector dataset field aliases in INTREPID database file and data structures R05 for more information about aliases Library Help Top 2012 Intrepid Geophysics 4 Back gt INTREPID User Manual Library Help Top gt gt To
42. ucial clock count units as stored in the Fiducial field Where to find information about spectral domain filters See Filter operations and Creating the extended region for filters and the early sections of INTREPID spectral domain operations reference R14 for a description of the pre and post transformation processes See Power Spectrum display for instructions about displaying the power spectrum graph for a filter See INTREPID spectral domain operations reference R14 for a full description of these filters Band Pass and Band Reject filters If you choose Band Pass or Band Reject INTREPID displays the corresponding filter properties dialog box Band Pass Filter Properties Band Pass Filter Properties Filter Name BandPass Unttied Filter Space FOURIER Filter Properties Low Cut Off Frequency ono in cycles km Cut Off Roll Off Parameter C cycles km High Cut Off Frequency ay in cycles km Cut Off Roll Off Parameter C cycles km No of Weight Control Points Extend D ata U sing Zero Pad Mirror Pad Data Flipped Mirror Pad Data Roll Off Using Bartlett Window Hanning Window Parzen Window Roll Off Window Size Accept Cancel Band Reject Filter Properties Band Pass Filter Properties Filter Name BandReject Untitled Filter Space FOURIER Filter Properties Low Cut Off Frequency in cycles km Cut Off Roll Off Parameter a cycles km High Cut Off Frequency Es in
Download Pdf Manuals
Related Search