I mean, just looking at our eyes: it's a field of evenly spaced measurement devices that send a direct signal to out brain. Ie we have a "parallel transmission of pixels".

You then just check what colour has the strongest (most) signals.

Or do you mean something else? Like how to do that consciously or something and not like, how it's possible?

Our rods and cones are no where near uniformly distributed, even after accounting for the blood vessel running around the retina.

If so, just add another layer that biases the result based on actual distribution.