Andreas, There is sure a non-linear conversion to fit 12bit sensor output into 8 bit data being compressed (see http://www3.elphel.com/linuxdevices/articles/AT9913651997.html ). This non-linear conversion (defined by gamma settings in camera settings) is designed to match the sensor output noise (mostly shot noise). The conversion parameters are saved in Exif headers, I would recommend you to try ImageJ plugin - it converts JP46/JP4 images to linear (32-bit TIFF), and it is GPL-ed software with the source code you can reuse in other projects. Here it is:
http://elphel.git.sourceforge.net/git/gitweb.cgi?p=elphel/ImageJ-Elphel;a=blob;f=JP46_Reader_camera.java Andrey These are illustrations from that article: http://docs.elphel.com/linuxdevices/AT8926870933_files/elphel_images/fwc_01.png http://docs.elphel.com/linuxdevices/AT8926870933_files/elphel_images/fwc_02.png On Wed, Nov 16, 2011 at 9:49 AM, Andreas Bean <[email protected]> wrote: > Andrey, > > After investigating the problem more deeply I found out that the reason > for my problem with the hsv saturation is a nonlinear camera response > against the exposure time. > > Is there any processing done in the camera before saving in jp46 mode? > > Do you have any idea why the response of the r g b pixel values is not > linear with exposure time? > > Andreas > > ______________________________**_________________ > Support-list mailing list > [email protected].**com <[email protected]> > http://support.elphel.com/**mailman/listinfo/support-list_** > support.elphel.com<http://support.elphel.com/mailman/listinfo/support-list_support.elphel.com> >
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