fmw42 wrote:Just curious if you have any idea why the two best individual colorspaces do not combine to give the single best dual colorspace result?
Oh, I see what you mean. Well, the situation is quite close to that. The top two single colorspaces are HSB and YDbDr. As a pair, they rank equal 8th out of 435, so quite close to the top.
I think that the score from every pair is better than either colorspace alone (but I haven't checked this). I aso think the ranking of multiple colorspaces depends on how "different" the colorspaces are. Do they measure different things? Down at the bottom of the rankings we have pairs like (YCbCr,YCC), (CbCr,YCbCr) and (CbCr,YCC) where (I assume) the colorspaces within each pair are very similar.
fmw42 wrote:I understand now about the need for the mean. It is not more accurate, but simply a way to make comparisons of different combinations colorspace (channels) easier.
That's it, exactly.
Where colorspaces (or combinations of colorspaces) rank close together, I don't think we can say for certain which is best. When I adjust the attacks slightly, the ranking order also changes slightly. Which combination of attacks is most representative of our needs? I don't think we can really say.
And there are other ways of doing rankings. I've grouped results by number of colorspaces. Instead, I might group by total number of channels, or lump them all together but apply a handicap to combinations with more colorspaces.