Abstract
The purpose of illumination is to allow solid perception to be obtained and depicted by a shaded pattern produced by lighting. The shading cue, as one of solid perception cues, was investigated, using a computer graphic device: Tospix-2. The corrugated wave was chosen for a test pattern, because an alternately bright and dark pattern, produced by shading, could be conveniently analyzed into contained spatial frequencies. This paper reports spatial frequency properties contained in the shading pattern. The shading patterns, which were actually shaded or were produced by computer simulation, were analyzed by Fourier Transformation by the same device. The result of the analysis indicates that the third through higher harmonics components are important. For observation of a solid shape, flat planes are assumed to be on the bottom of the completely curved solid perception. As apparent evidence for this assumption, under difficult visual conditions, a flat paneled figure was seen, in spite of the curved solid.
