I am just struggling to find the range of various color spaces I am trying to use in my program in OpenCV. I am sure that HSV range from 0-180 for H, 0-255 for S, 0-255 for V and RGB range from 0-255, 0-255, 0-255 for R,G and B. Please anyone can confirm the range of LAB, LUV and YUV?
Range depends to datatype.
Again, looking at cvtColor doc
Y = 0.299*R + 0.587*G + 0.114*B
Cr = (R-Y)*0.713 + delta
Cb = (B-Y)*0.564 + delta
Y componets represent luma, its coefficients sums 1 than Y has same range of RGB.
Cr, Cb represent color difference that can be max +/- 50% of the range. Given that delta is defined to be half of data type range, we can conclude that, in OpenCV, Cr and Cb cover whole data type value.
definitely, if data type is 8-bit
Y: 0 -> 255 , Cr:0.58 -> 255.45, Cb: 0.58 -> 255.42
Cr(min): R=0 G=255 B=255 Cr(max): R=255 G=0 B=0
Cb(min): R=255 G=255 B=0 Cb(max): R=0 G=0 B=255
I don't know if OpenCV uses integer aritmetic or simply round it. In case of round it becomes
Y: 0 -> 255 , Cr:1 -> 255, Cb: 1 -> 255
Concluding...may be the doc could be more explict as is for other color conversion
I would suggest you to add a pull request with the mentioned extra documentation?
Asked: 2015-06-02 09:03:20 -0600
Seen: 3,536 times
Last updated: Jun 04 '15
this helps ? cvtcolor doc
Thanks for your comment.
Still need some clarification regarding YUV range. It is mentioned in the OpenCV documnetation as Y, Cr, and Cb cover the whole value range.
If so, is it 0-255 for Y,U and V component?
Thanks..