[subb]

Consider that just after the cone cells, there are other cells doing some computation / aggregate of cone signals. Don't forget that color is a brain construct.

For those reasons (and others), there's often a strong disconnect between stimuli and perception, which means there's no such thing as a perceptual uniform color space.

[geon]

The eyes even do edge detection before sending signals to the brain.

[brookst]

Is this correct? I thought edge detection was done in the primary visual cortex.

[subb]

Sidestepping what is defined as an "edge", quite a lot of work is done in the retina, including differential computation across cones - some "aggregator" cells will fire when it detect lines, movement, etc.

You can read on ganglion cells, bipolar cells and amacrine cells and see that a lot of preprocessing is done before even reaching the brain!

[geon]

http://www.rctn.org/bruno/psc129/lecture-notes/vis-info.html....