ABSTRACT
Monocular Clues Looking out of a window, you can see that your image of the world has depth. You don’t need to move around to see this. Even if your window is only a single peephole, so that your viewpoint is one-eyed and fixed, the world still doesn’t look flat. Why should it? After all, it doesn’t look flat in a photograph, or even in a sixteenthcentury painting. In fact, with a fixed monocular (one-eyed) viewpoint there are four clear clues to depth, and you perceive these quite automatically.
