Fig. 1.

Examples of the correlation between intensity and depth in natural scenes. (A) Shadows (Left) are produced in the crevasses (range data, Right) of piles of objects. Lighter means farther for the range data images (blue regions were not recorded because they were beyond the range of the scanner). (B) There are also shadows seen in the more distant sections of foliage. (C) Correlation between relative luminance and relative depth using four different metrics (Materials and Methods). (D) Given two pixels, the one that is lighter is more likely to be nearer. Statistical significance of these measurements is described in Materials and Methods.