Typical studies of the visual motion of specularities have been concerned with how to discriminate the motion of specularities from the motion of surface markings, and how to estimate the underlying surface shape. Here we take a different approach and ask whether a field of specularities gives rise to motion parallax that is similar to that of the underlying surface. The idea is that the caustics that are defined by specularities exist both in front of and behind the underlying surface and hence define a range of depths relative to the observer. We asked whether this range of depths leads to motion parallax. Our experiments are based on image sequences generated using computer graphics and Phong shading. Using low relief undulating surfaces and assuming a laterally moving observer, we compare the specular and diffuse components of the resulting image sequences. In particular, we compare the image power spectra. We find that as long as the undulations are sufficiently large, the range of speeds that are indicated in the power spectra of the diffuse and specular components will be similar to each other. This suggests that specularities could provide reliable motion parallax information to a moving observer.

Date Published: 12 February 2007
PDF: 10 pages
Proc. SPIE 6492, Human Vision and Electronic Imaging XII, 64921A (12 February 2007); doi: 10.1117/12.702561

Published in SPIE Proceedings Vol. 6492:
Human Vision and Electronic Imaging XII
Bernice E. Rogowitz; Thrasyvoulos N. Pappas; Scott J. Daly, Editor(s)