Changes between Version 121 and Version 122 of UvmatHelp


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Timestamp:
Dec 7, 2014, 6:48:06 PM (10 years ago)
Author:
sommeria
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  • UvmatHelp

    v121 v122  
    154154-'''Keyboard short cuts:''' the activation of the push buttons  '''[runplus]''' and  '''[runmin]''' can be performed by typing the key board letters 'p' and 'm' respectively, after the UVMAT figure has been selected by the mouse. Similarly the command of the push button '''[run0]''' can be performed by typing the 'return carriage' key.
    155155
    156 === 3.5  Image documentation files (.xml) ===
     156=== 3.5  Image documentation files (.xml) === #ImaDoc
    157157Image series in UVMAT are documented by a file providing image timing, geometric calibration, camera type and illumination. This file is in the format ''XML'', a hierarchically organised text file. The content is labelled by tags, represented by brackets <.>, whose names and organisation are specified by a schema file (.xsd). A general introduction to the XML language and schemas is provided for instance in http://www.w3schools.com/xml. The schema used for image documentation is ''!ImaDoc.xsd'', available in the UVMAT package in a sub-directory ''/Schemas''. Simple templates of XML files are also provided there.
    158158
    159 When a new file series is opened in UVMAT, the XML documentation file is automatically sought in the folder containing the data series folder: the documentation of the file series !RootPath/SubDir/RootFile_1,... is in the file !RootPath/RootFile.xml. As a second choice (corresponding to an earlier convention), the XML file will be sought inside the data series folder, as !RootPath/SubDir/RootFile.xml (if this file does not exist, a text file with the same root name but extension .civ is sought as an obsolete option). The detection of the image documentation file is indicated by the visibility of the pushbutton '''[view_xml]''' on the upper right of the GUI '''uvmat.fig'''. Press this button to see the content through an XML editor '''editxml.fig''' (described in [#a10-Processingfieldseries section 10]). The XML file can be also opened directly by the UVMAT browser, or by any text editor. In UVMAT, it is read by the function ''imadoc2struct.m''.
     159When a new file series is opened in UVMAT, the XML documentation file is automatically sought (by the function ''find_imadoc.m'') in the folder containing the data series folder: the documentation of the file series !RootPath/SubDir/RootFile,... is sought in the file !RootPath/RootFile.xml. As a second choice (corresponding to an earlier convention), the XML file will be sought inside the data series folder, as !RootPath/SubDir/RootFile.xml (if this file does not exist, a text file with the same root name but extension .civ is sought as an obsolete option). The detection of the image documentation file is indicated by the visibility of the pushbutton '''[view_xml]''' on the upper right of the GUI '''uvmat.fig'''. Press this button to see the content through an XML editor '''editxml.fig''' (described in [#a10-Processingfieldseries section 10]). The XML file can be also opened directly by the UVMAT browser, or by any text editor. In UVMAT, it is read by the function ''imadoc2struct.m''.
    160160
    161161The XML file <!ImaDoc> can contain the following sections, as prescribed by the schema file ''!ImaDoc.xsd''.:
    … …  
    570570-'''3D_quadr:''' this is like 3D_linear, but takes also into account a quadratic deformation by the optics which occurs for wide fields of view (small focal lengths).
    571571
    572 -'''3D_extrinsic:''' this is like 3D_quadr, but uses intrinsic parameters of the camera, as explained below. '''''''''''
     572-'''3D_extrinsic:''' this is like 3D_quadr, but uses intrinsic parameters of the camera, as explained below.
    573573
    574574The 3D options involve a full 3D calibration relying on the [attachment:3D_view.pdf pinhole camera  model]. The method was first proposed by R.Y. Tsai, 'An Efficient and Accurate Camera Calibration Technique for 3D Machine Vision'. Proceedings of IEEE Conference on Computer Vision and Pattern Recognition, Miami Beach, FL, pp. 364-374, 1986). We use a more recent version, with the toolbox [->http://www.vision.caltech.edu/bouguetj/calib_doc/] . 3D calibrations are done in two steps. The camera'' intrinsic parameters'', which are the focal length and the quadratic deformation coefficient, are first determined by different views of the same grid observed at different angles. Then the ''extrinsic parameters'', which represent the rotation angles and translation of the physical coordinates with respect to the camera, are obtained with a single image of the grid positioned in a known plane $z=cte$. The option 3D_extrinsic allows the user to do only the second step from known intrinsic parameters. Those depend only on the camera with its objective lens and focus adjustement. Note that these 3D options require a calibration grid, with a sufficient number of calibration points covering the whole image.
    575575
    576 The transform coefficients for each image series are stored in the corresponding XML documentation file <!ImaDoc>, described in [https://servforge.legi.grenoble-inp.fr/#a3.5Imagedocumentationfiles.xml section 3.5],  under the tag <!GeometryCalib>.   Calibration coefficients  can be displayed with the GUI '''geometry_calib.fig''' described below. Field transform from pixel to physical parameters is performed by the function ''phys.m'' in UVMAT/transform_field, which calls the pointwise transform functions  ''phys_XYZ.m'' (from image to physical coordinates) and ''px_XYZ.m'' (from physical to image coordinates), as well as ''phys_ima.m'' which transforms images.  When an image or PIV velocity field is opened by uvmat, the transform function 'phys' is automatically loaded as described in section 4.6.
     576The transform coefficients for each image series are stored in the corresponding XML documentation file <!ImaDoc>, described in [https://servforge.legi.grenoble-inp.fr/#ImaDoc section 3.5],  under the tag <!GeometryCalib>. Calibration creates an xml file, or updates an existing xml file <ImaDoc>, with the name of the DataSeries folder containing the images currently opened by uvmat, followed by the file extension .xml. If a new data series is produced in a folder named with an extension, for instance DataSeries.civ for PIV, the xml file DataSeries.xml is still used, except if a new xml file DataSeries.civ.xml also exists.
     577
     578 Calibration coefficients  can be displayed with the GUI '''geometry_calib.fig''' described below. Field transform from pixel to physical parameters is performed by the function ''phys.m'' in UVMAT/transform_field, which calls the pointwise transform functions  ''phys_XYZ.m'' (from image to physical coordinates) and ''px_XYZ.m'' (from physical to image coordinates), as well as ''phys_ima.m'' which transforms images. When an image or PIV velocity field is opened by uvmat, the transform function 'phys' is automatically loaded as described in [#a4.6Fieldtransforms section 4.6].
     579 
    577580
    578581=== 8.2 The GUI geometry_calib.fig ===
    579 -''' Opening the GUI: ''' it is made visible  from the GUI '''uvmat.fig''' by  the menu bar command '''[!Tools/Geometric calibration] '''.  If calibration data already exist in the current file <!ImaDoc>, the corresponding parameters and the list of reference points are displayed in the table '''[!ListCoord]'''. The three first columns indicate the physical coordinates and the two last ones the corresponding image coordinates (in pixels). The physical unit is imposed as centimeter by the menu '''[!CoordUnit]''' to avoid mistakes. Calibration points can be alternatively introduced by opening any XML file <!ImaDoc> with the menu bar command '''[Import]''' of '''geometry_calib.fig'''. It is possible to import the whole information, option 'All', the calibration point coordiantes only, or the calibration parameters only.
     582-''' Opening the GUI: ''' it is made visible  from the GUI '''uvmat.fig''' by  the menu bar command '''[!Tools/Geometric calibration] '''.  If calibration data already exist in the current file <!ImaDoc>, the corresponding parameters and the list of reference points are displayed in the table '''[!ListCoord]'''. The three first columns indicate the physical coordinates and the two last ones the corresponding image coordinates (in pixels). The physical unit is imposed as centimeter by the menu '''[!CoordUnit]''' to avoid mistakes. Calibration points can be alternatively introduced by opening any XML file <!ImaDoc> with the menu bar command '''[Import]''' of '''geometry_calib.fig'''. It is possible to import the whole information, option 'All', the calibration point coordinates only, or the calibration parameters only.
    580583
    581584-''' Plotting calibration points: ''' press the button '''[PLOT PTS] ''' to visualise the current list of calibration points. The physical or image coordinates will be used in the list '''[!ListCoord]''', depending on the option blank or 'phys' in the menu '''[transform_fct]''' of ''' uvmat.fig''' .