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1. pa sux We a e CAD ek eae Eee BE 1 2 Camera Selection o cue pedea eeu nen Um Re eA ede ban os e rdg goon AUR l3 EIE 2 A A ees a d e Ee e c A 1 3 1 Taking automated readings 1 4 Measurement and Data ita ah Sree ade eg ea ee d eae L4 attribute dialog cs sr a ko oo mo gom bom Eo REESE es 1 4 2 Remove attribute 1 5 Saving and loading files 1 5 l dma ges s a ee pew d NUR e A ect a SO nos 1 5 2 Saving data in text files 1 5 3 Saving data in XML format 2 0 0000000204 1 5 4 Loading back from XML files 2 An average session with CamMeter 2 1 Preparation and 2 2 Processimg the pictures udo A doer BO ed 2 3 Saving data further work A Technical details A l System requirements an ee A 2 Organisation of code AS Availability secus ehe fieri Ur xD ewe Be ure x A 4 Specification of the CamMeter XML format 2s Ach Legal notices es Re ROGER UR REEL ead Rob EUR BORA 10 10 11 11 11 12 Chapter 1 Features The application normally consists of one single window containing a number of panels each re sponsible for some functions There are2. 2 1 Preparation and measurement Place everything you want to take a reading of reasonably close to each other so that you can put them in the scope of the camera at one time with everything well readable This is easy with digital meters but can be tricky with analogue devices or mechanical phenomena you may want to use a high resolution webcam or attach a digital camera Then adjust the webcam so that it sees everything you want to record in a quality that allows taking readings For this open the webcam in the Camera Selection panel use the highest default resolution unless you have a very good reason to do otherwise check the picture with the Preview button and adjust until you are happy with what you see Remember the only information you will get to take the reading is the camera picture If the preparation is ready you can start doing the actual measurement Prepare the equipment then choose a folder for saving files the best is to create a new one and hence start the timer If you wish to use automated readings enter the period and press Start automatic readings after the Start button Now start the experiment if you don t use automated readings press the Take reading button when you want to take a picture When the experiment is over press the Stop button 2 2 Processing the pictures Decide what quantities you want to record from the pictures Generally it is not worth to record anything but the ve
3. CAMMETER WEBCAM MEASUREMENT SOFTWARE VERSION 1 0 1 USER MANUAL AND DOCUMENTATION Attila Szab 2014 Copyright 2014 Attila Szab Permission is granted to copy distribute and or modify this document under the terms of the GNU Free Documentation License Version 1 3 or any later version published by the Free Software Foundation with no Invariant Sections no Front Cover Texts and no Back Cover Texts You should have received a copy of the GNU Free Documentation License along with the IXTEX 2e version of this documentation If not see http www gnu org licenses Preface In sub research level physics that is in secondary school and even in the first years of undergraduate physics courses the most used experimental tools if experiments are done at all are handheld meters electric multimeters thermometers and the like and naked eye observation of mechanical phenomena Normally we need to record more quantities each read off from different places possibly as a function of time which means an other reading from a stopwatch For example we may want to measure the resistance of a circuit element e g a thermistor as a function of temperature and also the cooling curve of the element i e the temperature versus time From a point on taking readings of multiple meters let alone more difficult tasks at the same time is very difficult and can only be done with teamwork of multiple people and or great discipline and organ
4. d 6 CHAPTER 1 FEATURES 1 2 Camera Selection This panel allows choosing from the webcams attached to the computer or switching them off altogether The resolution can also be selected for each camera and a preview can be displayed Camera the box contains all cameras attached to the computer and a special value No camera selected When selected the camera is opened at its highest resolution or any open camera is closed Resolution this box contains all resolutions supported by the selected camera in decreasing order When selected the camera is reopened at the chosen resolution IMPORTANT opening a camera or changing its resolution takes a few seconds during this time the program does not respond By a useful bug the boxes don t close up during this time don t click on anything in the window during this time Always set up the camera before starting the measurement It may be a good idea to take a preview photo before starting this would confirm everything is set up correctly and the camera sees what it should Preview if a camera is open pressing the Preview button takes a picture with the camera at the given resolution and displays it in the Image Display panel The picture is not saved anywhere The aim of this function is to check what is shown by the camera before starting the measurement IMPORTANT a webcam can be used by only one program at a time While using the webcam to record for CamMeter it is unava
5. e dot in English comma in most other European languages 1 234 Enter the numbers with the decimal separator that fits your program as it is not corrected by CamMeter anyway if you won t process them further use whatever you like 1 4 1 Add attribute dialog After clicking the Add attribute button this dialog pops up You may select where you want to place the new annotation field and what its name should be Place the new attribute before specifies the place of the new field in the table The default is to end meaning the new field appears right before the Image filename field which always comes last or to the right end if there are no pictures You may select any of the annotation coloumns then the new coloumn comes before that one Attribute name obvious IMPORTANT the dialog does not work before starting the measurement Add attribute Place the new attribute before to end v Attribute name Current Add Cancel Figure 1 2 the Add attribute dialog 8 CHAPTER 1 FEATURES 1 4 2 Remove attribute dialog After clicking the Remove attribute button this dialog pops up The only field is the box Select attribute to remove If a field is selected and removed all data from that coloumn are removed Remove attribute Select the attribute to remove Voltage v Remove Cancel Chart Taba rasdina Figure 1 3 the Rem
6. hough it would run without one There are no other hardware requirements the program is lightweight it uses only a few memory and hard drive space of course saving the pictures needs space No special libraries or drivers are needed if a webcam is recognised by the computer so it can be used in e g Skype it will work well for CamMeter A 2 Organisation of code CamMeter is open source see details below All program files are in the folder uk ac cam as2372 their content is as follows 1 stopwatch Runner java base class of the timer generates Reading objects upon request 2 stopwatch Reading java stores a timer reading and returns it in various formats 3 cammeter AnnotatedReading java subclass of Reading stores image filename and anno tation fields as well 4 cammeter Measurement java all data related to one reading series Stores annotation field names and readings provides methods for saving and loading files 5 cammeter MeasurementTableModel java subclass of Java s AbstractTableModel which renders a Measurement object for a Java table 6 cammeter TimerPanel java the Timer panel T cammeter CameraSetupPanel java the Camera Selection panel 8 cammeter PicturePanel java the Image Display panel 9 cammeter MeasurementPanel java the Measurement and Data panel 10 cammeter AddAnnotationDialog java the Add attribute dialog 11 cammeter RemoveAnnotationDialog java the Remove attrib
7. ilable to other programs e g you can t take a video recording 1 3 Timer This panel is dealing with everything related to timing including starting and stopping measure ments taking readings and setting up automatic readings The timer itself is located at the top of the panel Start when clicked on the button pops up a file opener dialog which allows to choose a folder where all files pictures and text outputs are saved If you cancel the reading doesn t start upon choosing the folder the timer starts running from 0 At this point the button label changes to Stop so clicking again stops this measurement it can t be restarted Take reading obvious Under these buttons a message Files are saved to is displayed during running measure ments IMPORTANT image filenames are always saved by full absolute path Do not change the path of the files saved by the program set up a folder the program may use happily before starting the measurement so you don t want to move anything later 1 3 1 Taking automated readings A facility is available to take readings at given intervals without pressing the Take reading button repeatedly Automatic reading interval the number entered here gives the period of readings in seconds Enter a number without any units or anything else not intelligible as a number You may enter non integer numbers as well 1 4 MEASUREMENT AND DATA 7 IMPORTANT it
8. in time annotation and image elements Their contents is specified below A lt field gt element shall have a type attribute This can have the following values e time hms time in HMS format Such a field must appear here and implies a time element of type attribute hms within each lt reading gt element e annotation an annotation field The element must have text content this gives the name of the field Such a field implies an lt annotation gt element in each lt reading gt element with a type attribute of the specified field name e image image filename field This element implies an lt image gt element in each lt reading gt element The order of annotation lt field gt elements in the file shall indicate their order in the CamMeter data table as a good practice the time element should come first and the image one last to comply with this ordering Each lt reading gt element shall contain exactly one lt time gt and at most one lt image gt element and any number of lt annotation gt elements They all shall be indicated by the lt field gt elements in lt record gt and shall have attributes as described above All of these elements shall have the contents of the appropriate data table cell as text contents A valid CamMeter XML file shall not contain any elements other than those specified above A 5 LEGAL NOTICES 15 A 5 Legal notices CamMeter is licensed under the GNU General Public License The fol
9. isation This is difficult A good solution can be taking photos of the equipment at times and read off from the pictures afterwards This can however easily go very cumbersome we would normally view the photos back on the computer where we would record the data too taking photos requires a camera and attendance this can become a problem in a long experiment we still need a stopwatch to time the photos properly CamMeter is a lightweight program to overcome most of such difficulties It uses a webcam joined to the computer webcams are cheap may already be present in labs and are already built in laptops Readings are automatically timed by a stopwatch based on the computer they can be triggered manually or automatically allowing us to leave the experiment alone The application window also contains a panel where readings can be recorded in the same window as the pictures are shown This document is the user manual of CamMeter I tried to give a simple and complete descrip tion of the program s features and a step by step guide to using the program in usual measuring scenarios Tam happy to see that experiments carried out by students gain larger importance in secondary school education too I hope that CamMeter will be a tool of good use in such experiments and will allow students to do more complicated but also more interesting measurements Best of luck with CamMeter Attila Szab Contents 1 Features LL Image Display
10. lowing notice is added to all source code Copyright 2014 Attila Szabo CamMeter is free software you can redistribute it and or modify it under the terms of the GNU General Public License as published by the Free Software Foundation either version 3 of the License or at your option any later version CamMeter is distributed in the hope that it will be useful but WITHOUT ANY WARRANTY without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE See the GNU General Public License for more details You should have received a copy of the GNU General Public License along with CamMeter If not see lt http www gnu org licenses gt This documentation is licensed under the GNU Free Documentation License available at http www gnu org licenses fdl 1 3 txt CamMeter uses an additional webcam capture library for Java written by Bartosz Firyn avail able at http webcam capture sarxos p1 This library is licensed under the MIT License 16 APPENDIX A TECHNICAL DETAILS
11. ng your file i Please make sure you try to open a CamMeter XML file and try again Figure 1 6 the error message after trying to load an invalid file 10 CHAPTER 1 FEATURES A comment mark can be placed at a specified place in each row This is useful to hide possible text fields from programs that process text files containing numbers e g gnuplot By default this is switched off by selecting a field from the Add a comment mark box a comment mark will appear right before that field hiding the field and everything that follows Finally the type of the file may be chosen The Save as text option saves the selected data in a tabulator separated text table with a short header including the field names This can be used to import in Excel or process by professional software gnuplot Matlab The Save as XML option saves the data in an XML file more on that in the next section 1 5 3 Saving data in XML format XML is a general purpose markup language that can store any kind of data in a format that is easy to read for both humans and computers CamMeter can save measurement data in a custom XML based format and also reload these files The format is specified in detail in appendix XML files are less straightforward to understand by the human reader than a table and also unreadable for Excel and other programs for data processsing this option is mainly for saving the project in a way that it can be continued later Saving g
12. o pictures were taken By default all fields are checked you may uncheck them by your choice Select all and Deselect all buttons are present to help with this The right half allows some fine tuning and setting the filename We may enter the filename which is set to measure by default not that this does not contain any extensions this may be a problem on Windows The file is saved in the same folder as the pictures 1 5 SAVING AND LOADING FILES Save into file Fields to save Settings v Time H MM SS mmm Add a comment mark before ime in E 7 Time in milliseconds v v Voltage Save into the filename v Time H MM SS mmm measure v Image filename 8 Save as plain text Save as XML Select all in Deselect all Save _ E _ FCS pte _ __ Figure 1 4 the Save into file dialog in text file mode Save into file Fields to save Settings v Time H MM SS mmm Add a comment mark before Time in milliseconds lv Voltage Save into the filename Time H MM SS mmm measure IR Image filename Save as plain text e Save as XML Select all Deselect all Save Cancel Figure 1 5 the Save into file dialog in XML mode An error occured while parsi
13. oes also from the Save data in file dialog which works roughly the same but there are some differences triggered by selecting the Save as XML option Time is always saved it is vital to reconstruct a measurement series in HMS format i e to full precision so checkboxes related to time fields are disabled in XML mode Commenting out is diabled as well it only makes sense for text file output You can still select which other fields to save and save the result with a filename of your choice the extension xml is recommended but reloading works fine without that too 1 5 4 Loading back from XML files An XML file saved by CamMeter can be reloaded using the Load data from XML button in the Measurement and Data panel Clicking the button opens up a file chooser dialog where any file can be selected If the file was a valid CamMeter XML file the data of the measurement are loaded and displayed in the data table as if it was measured right now Otherwise an error message informing about the invalid file pops up IMPORTANT only XML files can be loaded trying to load a text file saved by CamMeter will also result in an error message Chapter 2 An average session with CamMeter This chapter describes how to use CamMeter in an actual measurement and collect the data from the picture in a way that makes saving and further use convenient Along with usage details some general ideas about data reading and processing are described too
14. ove attribute dialog 1 5 Saving and loading files 1 5 1 Images Pictures taken during measurements are saved automatically in the folder specified before starting the measurement They are saved in PNG format as this doesn t reduce the already not too high quality with the filenames 0 first reading 1 png These are hard coded and cannot be changed through the user interface Pictures are loaded automatically in the Image Display panel when clicked on the row corre sponding to them in the data table IMPORTANT filenames are always as specified If you save the pictures of two measurements in the same folder the latter will overwrite the former Always make a separate folder for all measurements 1 5 2 Saving data in text files After clicking on the Save data in file button the Save into file dialog will pop up This is used to export the saved and annotated data either in tabulated text format or in XML format see next section The left half of the dialog is the Fields to save frame it contains a checkbox for each possible field to export These fields include e Time of the reading in hour minute second mil HMS format at the start of the row e Time in some units mils seconds minutes hours Each annotation field Time in HMS format again it may be useful not to start the row with a basically text field but still have the time in a human readable format revisited later Image filename disabled if n
15. ry raw data you can directly read off since you can compute these later with the computer saving manual work Also CamMeter can t produce graphs or the like you ll eventually need to export the data in some software capable of this they normally can deal with computations Create coloumns for each such quantity using the Add attribute button Each field name should make obvious what is recorded there and in what units always record pure numbers in the table If you have any fields that would bear text information it is a good idea to put them at the end of the row placing all numbers in the front Field names can t yet be corrected if you want to change one remove it and add again that s why you should set up the coloumns in advance Now start reading off the pictures and record the data you see If you click on any cell the picture corresponding to it will appear in the Image Display panel Enter the numbers without any 11 12 CHAPTER 2 AN AVERAGE SESSION WITH CAMMETER non numeric character e g units taking care of the decimal separator convention your other software uses If you need to interrupt the readings make sure you save the data in XML format so you can reload it later and continue This may be a good idea anyway 2 3 Saving data further work When all data are recorded they can be saved in both text or XML formats It can be recommended to save everything selecting all checkboxes in XML forma
16. some additional dialogs for certain functions which pop up occasionally The subsequent sections introduce these layout elements and explain the functions available through them Timer Image Display Start Take reading id Hii L Files are saved to home attila cammeter gt y Automatic reading interval sec 1 A AA r ze Start automatic readings Camera Selection Camera Webcam HP Webcam 101 dev videoO Resolution 640x480 v AAA Preview Measurements and Data Time Voltage Image filename pee p 0 00 05 174 1 55 home attila cammeter 1 png A ae f E 1 02 home attila cammeter 2 png T d 1 43 home attila cammeter 3 png Remove attribute i 0 76 home attila cammeter 4 png Save data in file 00 0 33 home attila cammeter 5 png g 0 00 0 175 heme ttila cammeter 6 png Load data from XML 0 00 11 176 0 15 home attila cammeter 7 png Figure 1 1 a screenshot 1 1 Image Display The simplest panel of the program is the image display It provides no interactive features its only function is to display an image recorded by the webcam This panel is used by the preview see Camera Selection and measurement annotation functions see Measurements and Data The panel also provides a facility for selecting areas of the picture this is for a planned OCR backen
17. t anyway so the data can be reopened in CamMeter if needed It may happen that you are working further by hand then no other action is needed To save a text output select the fields you want to export If you are going to use a program that reads tabulated text files gnuplot for example make sure it will read only numeric fields uncheck the first Time H MM SS mmm field this is not a simple number and place a comment mark in front of the first text field that s why collecting them at the end is a good idea If the file is going to be read in by some other application e g Excel there is no need for the comment marks and you can export whichever field you want Give it an appropriate filename and extension csv works well with Excel and save A text file with properly placed comment marks can be used directly with programs like gnuplot and Matlab To import in Excel you can open it provided it has a good extension the only important issue is checking the delimiter settings the default might be something else than the tabulator this requires adjusting The first three rows are headlines which can be ignored Appendix A Technical details A 1 System requirements CamMeter is written in Java It can be run on all common operating systems Windows Mac Linux provided the Java Virtual Machine is installed this is free and already installed on most computers A webcam is very useful for using the program t
18. takes about 0 1 0 2 seconds of machine time to take and save a picture If you set a period shorter than this readings will still be taken at about this rate the data stacking up may crash the program A period shorter than 0 25 seconds is not recommended values over 0 4 seconds are absolutely fine Start automatic readings obvious You should always set a period before clicking the button After clicking the label changes to Stop automatic readings clicking again stops the reading series It is possible to start automatic readings more than once in the same measurement possibly with different periods 1 4 Measurement and Data This window contains the table where all data in the current measurement are displayed Annota tions can be entered directly in the table but time and image fields cannot be modified Initially the data bear no annotation fields the only coloumns are Time and Image filename if pictures were taken Fields may be added using the Add attribute button and removed using the Remove attribute button To enter an annotation click on the appropriate cell of the table and type If pictures were taken the picture corresponding to this reading is displayed in the Image Display panel allowing to take the reading from the picture without switching windows IMPORTANT take care of decimal separators Command line tools e g gnu plot always require a dot e g 1 234 For Excel it depends on the languag
19. ute dialog 13 14 APPENDIX A TECHNICAL DETAILS 12 cammeter SaveDialog java the Save into file dialog 13 cammeter MainFrame java the main class of the whole program that creates the application window The code is explained more in detail by accompanying comments in the program files A 3 Availability The source code the compiled program and this documentation are all available from the web site http people ds cam ac uk as2372 cammeter where updates and new versions may be published Everyone is free to redistribute CamMeter in any way either as it is or in any modified form You are however legally required to make the source code of the program available for anyone who can access the executable program through you Any queries or discovered bugs should be reported to as2372 cam ac uk A 4 Specification of the CamMeter XML format A CamMeter XML file shall contain a single lt measurement gt root element containing all informa tion This shall contain the following three kinds of elements e One lt meta gt element any metadata relating to the measurement can be recorded here Con tents are not specified further CamMeter 1 0 adds a single lt vendor gt field e One lt record gt element this may only contain lt field gt elements each describing one field recorded in the XML file as specified below e Any number of lt reading gt elements each of them contains data related to one reading
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