Figure 3.

Statistical relationship between the spatial intervals in the projected images and the corresponding physical intervals in 3D space. (A) Examples of the frequency distribution of the physical length to projected length ratio (λ, in meters/pixel) at four different θ values. The l in all three examples is 20 pixels. (B) The mean value of λ plotted as a function of the θ. Examples of the function obtained at three different l values (in pixels) are shown (see Materials and Methods). (C) Normalized mean of λ averaged across all values of projected interval length plotted as a function of θ. The similarity of this curve to the psychophysical function in Fig. 1 indicates that the statistical relationship between projected length and physical length accords with the perceptual variation of apparent line length.