Hi,
For our project of soccer-playing robots, we use off-the-shelf WinTV
frame grabber cards to import from our Jai CVS3300 PAL cameras. We
noticed that the colors as displayed on our Philips PAL monitors were
different from the results from the grabber, using the Linux BTTV
driver. This is no big surprise in itself, but it led us to look into
the driver source code, and we noticed that a different gain is used
for U and for V in bt848_sat():
/* 0-511 for the color */
val_u = color >> 7;
val_v = ((color>>7)*201L)/237;
We looked in the BT878 PDF document (127 pages), and found no reason
for this factor. Can anyone explain what this factor is for?
Is it to make RGB conversion "nicer-looking"? In that case, since we
do our object segmentation in YUV space (and actually grab images in
YUYV format, can we remove the factor from the driver?
Thanks in advance,
Frank de Jong
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Frank de Jong (frankdj@xxxxxxxxxxxxxxxx)
"Real hackers don't die, their TTL expires."
