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I don't understand why they don't compare it with YCbCr, which is a very similar colorspace that is much more widely used than some of the obscure ones they com

by dTal 6y ago

I don't understand why they don't compare it with YCbCr, which is a very similar colorspace that is much more widely used than some of the obscure ones they compare it with - notably, in JPEG.

jacobolus 6y ago
YCrCb is roughly based on the ones mentioned (which are not at all obscure from the perspective of color science), but is supposed to be as computationally cheap as possible, and so doesn't bother doing even basic steps like undoing gamma encoding. As a result, YCrCb yields crappy results for any purpose other than image encoding. The further you get from neutral gray, the worse YCrCb gets at cleanly separating lightness from hue/chroma.
- bjornornorn 6y ago
  Yeah, that’s pretty much why I didn’t include it. I haven’t really seen YCrCb used except anywhere for in compression, so didn’t think of including it (an neither do most papers related to perceptual color spaces).
  - thewebcount 6y ago
    It was used quite a bit in video editing in the early 2000s because the video frames often came from disk or a card in that format, and you could do some fast processing tricks with it. Those days have largely passed, though.
batty_alex 6y ago
I was thinking the same thing. My guess is the author’s background is in games and that’s where this research is focused. It did give an impression that, to someone who works with color spaces, the author is operating in a different domain
HelloNurse 6y ago
YCbCr was designed for the needs of analog color TV transmission and recording, not for image processing and editing.
- batty_alex 6y ago
  Person your responding to isn’t asking about that particular color space. They’re asking for some real-world examples. This is a very theoretical piece about color spaces that intersects with a very particular use of color spaces. YCbCr was definitely not designed for analog tv. That color space is for digital video and imaging
kelsolaar 6y ago
Y’CbCr is simply not perceptually uniform, it is a simple rotation of RGB to separate better Luma and Chroma and thus be able to compress the latter more to leverage our lesser sensitivity to colour variation.

by dTal 6y ago

I don't understand why they don't compare it with YCbCr, which is a very similar colorspace that is much more widely used than some of the obscure ones they compare it with - notably, in JPEG.

jacobolus 6y ago

YCrCb is roughly based on the ones mentioned (which are not at all obscure from the perspective of color science), but is supposed to be as computationally cheap as possible, and so doesn't bother doing even basic steps like undoing gamma encoding. As a result, YCrCb yields crappy results for any purpose other than image encoding. The further you get from neutral gray, the worse YCrCb gets at cleanly separating lightness from hue/chroma.

bjornornorn 6y ago
Yeah, that’s pretty much why I didn’t include it. I haven’t really seen YCrCb used except anywhere for in compression, so didn’t think of including it (an neither do most papers related to perceptual color spaces).
- thewebcount 6y ago
  It was used quite a bit in video editing in the early 2000s because the video frames often came from disk or a card in that format, and you could do some fast processing tricks with it. Those days have largely passed, though.

batty_alex 6y ago

I was thinking the same thing. My guess is the author’s background is in games and that’s where this research is focused. It did give an impression that, to someone who works with color spaces, the author is operating in a different domain

HelloNurse 6y ago

YCbCr was designed for the needs of analog color TV transmission and recording, not for image processing and editing.

batty_alex 6y ago
Person your responding to isn’t asking about that particular color space. They’re asking for some real-world examples. This is a very theoretical piece about color spaces that intersects with a very particular use of color spaces. YCbCr was definitely not designed for analog tv. That color space is for digital video and imaging

kelsolaar 6y ago

Y’CbCr is simply not perceptually uniform, it is a simple rotation of RGB to separate better Luma and Chroma and thus be able to compress the latter more to leverage our lesser sensitivity to colour variation.