Changes between Version 7 and Version 8 of Tutorial/GeometricCalibration

Timestamp:

Aug 28, 2013, 3:18:41 PM (11 years ago)

Author:

sommeria

Comment:

--

Tutorial/GeometricCalibration

@@ -13 +13 @@
 To 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'''.
 
-To perform the calibration, press '''APPLY''', first with the default option 'rescale' in '''calib_type'''.  The image is now displayed in phys coordinates. 
+To 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
+'images.ref.xml' put for reference).
+
+= translating and rotating the coordinates =
+The 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).
+
+To 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'''. 
+
+
 
 
@@ -32 +40 @@
 To 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.
 
-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. 
+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 to about 1 pixel. The previous xml file has been saved with a ~, ('Dalsa1.xml~') so it can be reverted in case of error.