Perspective Space as a Model for Distance and Size Perception

The perspective structure of visual space

Human vision is extremely sensitive to equidistance of spatial intervals. Thresholds for spatial equidistance have been extensively measured in bisecting tasks. In spite of the vast number of studies, the informational basis for equidistance perception is unknown. There are three possible sources of information for spatial equidistance in pictures, namely, distances in the picture plane, in physical space, or visual space. Computational analysis shows that from the Middle Ages until now, artists either represented equidistance in physical space or in a visual space of very limited depth. Among the painters and engravers who depict equidistance in a highly non-veridical visual space are renowned experts of linear perspective.