This message is from: Marsha Jo Hannah <[EMAIL PROTECTED]>
> [EMAIL PROTECTED] wrote: > > I didn't think horses had depth perception in the first place? There are several forms of depth perception. Humans (and most predators) use "stereopsis"---both eyes viewing the same object, to "triangulate" the position thereof. Due to the placement of their eyes in their skulls, horses view most of the world with one eye at a time. However, there is a narrow triangle directly in front of them, where they can see objects with both eyes at the same time. Walk around your horse, both in close and at a moderate distance, and determine the locations from which you can see both of his eyes--- that's where he has standard depth perception. However, even a one-eyed human has a pretty good idea about depths, from "motion stereo". That's because, as we move thru the world, we keep track of how the view changes as we move. (Close one eye, and walk around, looking at the world as you move. You can still tell what is near and what is farther away.) The difference in position of objects within the eye's "image" as we move gives some information about how far away the objects are. The depth information derived this way isn't as precise as depth from stereopsis, but it'll do for most "navigation" in the world. (Anybody wanna guess the subject of my PhD thesis, and the 25 years I spent programming computers?) Marsha Jo Hannah Murphy must have been a horseman-- [EMAIL PROTECTED] anything that can go wrong, will! 15 mi SW of Roseburg, Oregon
