2004.08.12 21:07 "Re: [Tiff] From bmp to Tiff", by Andrey Kiselev

** color space **

Some people will dissagree, but in my opinion, 'blending' colors, or any color calculation like the 'pixel area averaging' described above, is an operation that only makes sense to the human eye. That is why, I think, you need a color space that makes sense to the human eye. CIE L*a*b* is most suitable in my experience. The further away from such a perceptually uniform color space, the less pleasing the results. For instance, RGB might still be relatively usefull for such algorithms, CMYK might not.

For image resizing, I am one of those who disagree. Image resizing is almost always done on a planar level so color perception is usually such a minor factor that it can generally be ignored. The most important factor with quality of image resizing is how well the algorithm antialises the results (avoids "jaggies") without excessively softening or otherwise distorting the image.

I should agree with Bob. I'm working with images which should be resized in the planar space, defined by the data format (i.e. floats should be resized as floats). Of course, there are can be cases when the color space becomes a valuable factor for the image perception, but it is not the major factor.

Anyway, your detailed answer should be added to FAQ and further discussed in the mailing list (I'm sure, there are a lot of image processing experts here).

Andrey

Andrey V. Kiselev
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