The visual perception of three-dimensional length.
A set of 4 experiments evaluated observers' sensitivity to three-dimensional (3-D) length, using both discrimination and adjustment paradigms with computer-generated optical patterns and real objects viewed directly in a natural environment. Although observers were highly sensitive to small differences in two-dimensional length for line segments presented in the frontoparallel plane, their discrimination thresholds increased by an order of magnitude when the line segments were presented at random orientations in 3-D space. There were also large failures of constancy, such that the perception of 3-D length varied systematically with viewing distance, even under full-cue conditions.
Norman
J F
JF
Department of Psychology, Ohio State University, Columbus 43210-1222. fnorman@magnus.acs.ohio-state.edu
Todd
J T
JT
Perotti
V J
VJ
Tittle
J S
JS
D017076:Computer-Aided Design; D003867:Depth Perception; D006801:Humans; D008297:Male; D009903:Optical Illusions; D012858:Size Perception