Changes between Version 7 and Version 8 of Tutorial/GeometricCalibration


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Timestamp:
Aug 28, 2013, 3:18:41 PM (8 years ago)
Author:
sommeria
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  • Tutorial/GeometricCalibration

    v7 v8  
    1313To see the calibration points on the image, first display the whole image by unselecting '''fix''' (tag '''[!CheckFixLimits]''') in the frame '''Coordinates''' of uvmat. Then press '''PLOT PTS''' in '''geometry_calib'''.
    1414
    15 To perform the calibration, press '''APPLY''', first with the default option 'rescale' in '''calib_type'''.  The image is now displayed in phys coordinates.
     15To perform the calibration, press '''APPLY''', first with the default option 'rescale' in '''calib_type'''.  The image is now displayed in phys coordinates. A xml file 'images.xml', containing the calibration parameters and reference point coordiantes, has been created in the folder 'UVMAT_DEMO01_pair' (it should be identical with the file
     16'images.ref.xml' put for reference).
     17
     18= translating and rotating the coordinates =
     19The origin of the phys coordiantes is now arbitrary. It is more convenient to have it for instance at the centre of the cylinder, now at (x,y)=(1.7, 4.0).
     20
     21To get the precise position of the cylindre, it is useful to introduce a projection point, using in '''uvmat''' the menu bar command Projection '''object/points'''.
     22
     23
    1624
    1725
     
    3240To perform the calibration, press '''APPLY''', first with the default option 'rescale' in '''calib_type'''. The image is now displayed in phys coordinates. We observe that the rectangular frame is slightly rotated. furthermore the displayed precision, about 3 pixels, is not excellent.
    3341
    34 To improve the precision we then apply the option 'linear' in '''calib_type''', which seeks a general linear transform, including rotation. The precision is indeed improved, about 1 pixel. The previous xml file has been saved with a ~ ('Dalsa1.xml~') so it can be reverted in case of error.
     42To improve the precision we then apply the option 'linear' in '''calib_type''', which seeks a general linear transform, including rotation. The precision is indeed improved to about 1 pixel. The previous xml file has been saved with a ~, ('Dalsa1.xml~') so it can be reverted in case of error.