I guessed you didn't mean a flat image too, but wanted to make sure that we are talking about same thing: a "3D model" instead of 2d flat image. I totally agree with you on your above quote.DaveW wrote:...Therefore I see no reason why an insects brain does not perform a similar combination of separate images to form a similar 3D version of what is around it.
Just like human eyes, it doesn't need to have a uniform resolution across the field of view. We humans have 1min-arc resolution at the fovea but that drops pretty quickly when you move away from the optical center.I cannot believe for instance a dragonfly can be so good at catching insects in flight if it is only seeing a rudimentary fuzzy image?
Being able to move our eyes and head lets us to sample the scene in parts on demand and progressively build a high-res model of the surrounding. After all although we have 100 million photoreceptors we have just 1 million nerves going to the brain but we think our vision is much better than 1 megapixel, that is true because with moving parts (both the visible eye movements and very small and fast jittering eye movements) we refine the image progressively. If you try to read just 4-5 lines above while staring at this dot (.), you realize how fuzzy even our stationary visions are but it's not a big issue in practice.
After checking the web for dragon-flies (which turned out to have ~30K ommatidia) I saw that they have a similar structure where in the central part there are much more receptors per angle. from http://www.daviddarling.info/encycloped ... d_eye.html
Compared with single-aperture eyes, such as the human eye, compound eyes have poor resolution so they are not good at making out detail. On the other hand, compound eyes have a very large angle of view and the ability to detect fast movement and, in some cases, the polarization of light. Insects that can fly well, such as honey bees and flies, or that catch prey, such as dragonflies or preying mantis, have specialized zones of ommatidia. These zones are organized into a fovea area that gives acute vision. In the acute zone, the eye is flattened and the facets are larger, which allows more ommatidia to receive light from a spot and thereby achieve higher resolution.
Compound eyes generally allow only a short range of vision. For example, flies and mosquitoes can see only a few millimeters in front of them with any degree of resolution, although within this short range they can see detail that we could see only with a microscope.
Dragonflies have one of the most elaborate eyes of any insect, capable of pinpointing the motion of a small prey insect several meters away, even his while the dragonfly is traveling fast. Butterflies have color vision that is more enhanced than our own, enabling them to locate food from flowers. Honey bees can see in ultraviolet, which allows them to perceive patterns on nectar-laden flowers that are invisible to us. Many insects, including bees, can also detect polarized light, which they use in navigation.