Sunday, August 10, 2008

Mimicking the human eye

We machine vision professionals understand that the modern digital camera is a very poor imitation of the human eye. One of the many ways in which it falls short is the shape of what we might call the photon receiving surface. In the eye this ‘retina’ is curved, which suits the optics of the lens. However, to date only flat CCD and CMOS sensors can be manufactured.

There’s an interesting article in the Chicago Tribune of August 7th that discusses work underway to develop a
curved photon-sensitive surface. More detail is given by the BBC. Unfortunately, it appears to be years away from production reality.

Why is this unfortunate? Well picture for a moment those lens diagrams that show the central ray and a peripheral ray. The peripheral ray has to travel further to reach the imaging surface, and this creates focus issues. Optical engineers endeavor to design out these problems, so we don’t typically experience different focus between the image center and the corners. But think how much easier optics might be if we had hemispherical light-sensing surfaces.

Now that really would be a step-change technology!

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