Rethinking the Process of Vision

Consider a thought experiment as to how the retina of the eye might have been organized from first principles. It would be a given that a library of pigment molecules sensitive to the various wavelengths of the visible spectrum (leading to the formation of an array of “laboratory-like spectrometers”) was not available. What nature did have available was a simple two-part rule that, a.) visible wavelengths could be absorbed between two adjacent quantum confined electron sites formed using a single molecular configuration - the retinal molecule, and, b.) that only the simplest combination of two geometric spacings between any such sites could be used. We next consider the spectrum of chromatically-aberrated light transmitted through the lens of the eye and falling on a retinal surface. The longest wavelength (red) wavelength would refract minimally and incident at around zero degrees of retinal angle (constituting the fovea) while shorter wavelengths, i.e., towards the blue end of the spectrum, would incident at larger angles to twenty degrees and beyond. With the above defined simplest components - and the ability to form three detector configurations in a mixed array - at it’s disposal, how would nature arrange these detectors on the retina? It seems clear that the only route would be to abstract from the band of wavelengths constituting the visible spectrum only three wavelengths corresponding to the three possible detectors. Such a retina would then actually ABSTRACT THE SHAPE OF THE SPECTRUM effecting an in-situ “color separation” of the spectrum much the same as is done today in the field of photographic printing. It would physically define the long and short wavelength ends and exact geometric middle of the spectrum Moreover, it would have encoded the intensity of the spectrum at each point as a DENSITY OF THE THREE DETECTOR SPACINGS.

The starting point of the vision process is then visible light interaction onto a physically-encoded record of the visible spectrum constructed from first principles from which each point of a visually perceive image might be referenced and a final color constant image computed. This is exactly what Edwin Land brilliantly deduced!

It is not inconsequential that such a physically encoded spectrum explains the unique color constancy of the biological vision process.

I note again that, in not getting to these fundamental principles, science hs “shot itself in the foot” in confronting the “intelligent designers” by historically visualizing the retina and vision process to be more complicated that it actually is!

This entry was posted on Monday, October 3rd, 2005 at 2:39 pm and is filed under Color Vision, Edwin Land, Fovea, Retina, Running Commentary . You can follow any responses to this entry through the RSS 2.0 feed. You can leave a comment, or trackback from your own site.