Advantages of Foveon sensor Locked

Started Jun 23, 2013 | Discussions thread
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Laurence Matson
Laurence Matson Forum Pro • Posts: 11,959
Walk before you run

Just another Canon shooter wrote:

Roland Karlsson wrote:

Bobn2 wrote:

What is a 'color gradient'?

To be more specific, what is a 'color'?

A good question.

For an RGB image, a color is an RGB triple in some color space.

In nature, "color" has infinitely many components, it is a "spectral density". Each sensor, Foveon or not, projects it on a 3D space in some way. So does the human eye. Bob's point is that Foveon senors have color vision farther away from the human eye than the Bayer ones. This has nothing to do with spatial separation. It is worse separation in another dimension, which is the spectral one.

If the Foveon sensors has a wider curve in the red part of the spectrum, this does mean that it can see "more colors" but also means that it cannot distinguish between them, like a B&W sensor (with no color filter). If that curve is significantly different than that of the human eye, then it is a poor approximation of the human vision.

Welcome to the Sigma Forum.

You need to read up a bit on how these imagers work. I think there are still some papers on the Foveon site. Otherwise, look up Dick Merrill, Dick Lyon, Paul Hubbel, Peter Manca, Rudy Guttosch for starters.

Not to be rude, but your second paragraph is a gem of fluff. There are "more colors" and specific wavelengths. I don't really see someone here is saying that a Foveon imager can see "more colors" but rather that it sees distinct colors at each spatial location where three pixels scrape together the electrons - simplistically speaking, dead photons (one step beyond Einstein's Nobel Prize winner - at each layer and come up with three sort of distinct numbers, which can be turned into a specific color.

I know, I know, I know, it is not that simple; otherwise, I would be doing what Eric M wants and rewriting Dave's code. But that is generally what goes on.

So the key is not that the Foveon imager can see more colors but rather that it theoretically can distinguish colors accurately, with a caveat on all of the last part of the phrase. Where the Bayer process relies on a brilliant method of exploring the surrounding pixels to determine what belongs between two good signals, the Foveon process relies on accurately interpreting collected information. Both are forms of interpretation, if you will.

Now Bob can shoot this down along with the others.

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laurence at appledore-farm dot com
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