What's the "pixel resolution" of the human eye?

What’s the “pixel resolution” of the human eye?

I’m guessing it’s the number of cone cells in the retina, but how many is that exactly? And can we really distinguish every point, or do they blur?

Would an eagle have more pixels, or is that hype?

Dunno what the pixel resolution is, but the dots definately blur. Pop a piece of a magazine or newspaper under a microscope. Whats looks like one solid color is really made up of really small, close together dots of various colors.

Apples and oranges. Human visual acuity cannot accurately be expressed in the context of CRT “pixels”/pels.

The idea that human sight can be infinitely divided is an illusion. The proof is that at certain pixel resolutions, at a given distance, you cannot distinguish a monitor from a mock-up with a photo on it.

The retina, of course, is not organized into rows, but there would certainly be a maximum number of nerve endings leaving the eyball. That should give the gross pixel count.

Wasn’t suggest there are no specific boundaries for human vision, only that attempting to measure human vision as analogous to a specific “picture element” density within the eye was not an appropriate or useful physical analog or metric for this determination.

How is is expressed?

The rods/cones are not organized in a neat grid, and the density of them is not uniform over the entire retina. Still…

At the center of the retina, say, where (I think) the density of receptors is highest, there’s gotta be some kind of threshold of resolution. How does one express this?


The properties of the human eye as a telescope…

Just to try to make the comparison: If the human eye has a resolution of one minute of arcand it can see a square of 90 degrees then it can see about 29 million pixels. That would give you an order of magnitude of what the image on the retina is like but the brain does not process all the information the same way. Most of that would be your peripheral vision where your resolution is much lower and only the fovea’s central vision would be so acute. So, for comparison purposes, I would make up a number in the order of 3 - 10 megapixels for human vision. You would also have to take into account that we have two eyes (at least I do) but this does not double your capacity, rather it gives you depth perception etc.

According to Waqrren J. Smith’s “Modern Optical Engineering” the cones (which detect color) are 1 to 1.5 microns (millionths of a meter) in diameter, while rods (B&W) are 2 microns. The separation varies with position, being more concentrated in the fovea, but average about 2 to 2.5 microns apart. Most CCD cameras have detector elementsd that are on the order of 10 microns acros, with a 10 micron pitch.

“Normal Visual Acvuity” is taken to be about one minute = 1/60 degree. This is the figure used in designing optical instruments.

Tom Cornsweet’s “Visual Perception” is the usual reference o such matters. If you look at the frequency response of the eye – which takes into account not only the detector spacing on the retina, but also the properties of the lens and other optical factors, then human eyes typically go down to about 1 cycle per degree. Some people are apparently good down to about a third of this.

Of course, this isn’t the end of it – the eye is connected to the brain, which provides a complicated analysis system for the visual input. (If you want an idea of how complicated, try to understand the Land effect for color vision) I had a discussion with one professor who was convinced that coherent effects between different “pixels” allowed for some resolution beyond the limit the above numbers imply.

Slightly off topic, but here’s a little bit about the cat-brain-cam:


And to further elaborate on not answering the question at hand, I recall reading somewhere that all color variation detectable by the human eye can be reproduced by a computer monitor’s 32-bit color scheme, or “millions of colors” if you have an Apple. But then again, Seurat did a creditable job with about eight colors, so I suppose I don’t don’t know what the hell I’m talking about.

Thanks guys! I knew there would be some number that could be calculated.