Abstract
Image characteristics in a 3D object contributing to the translucent perception is an interesting issue in understanding material perception. While Motoyoshi (2010) suggested a global cue in an object image for the translucency perception, the spatial contrast relationship between non-specular and specular components, local cues for the translucency perception have rarely been investigated. Here we intended to extract spatial regions related to the translucency perception for a CG object image with a psychophysical reverse correlation method. The stimulus was an image created by combining two CG images based on a two-dimensional random pattern, which caused a difference in perceptual translucency between multiple stimuli made from identical CG images. The observers simultaneously viewed two stimuli created based on different composition patterns, and judged which stimulus had stronger translucency. The composition patterns were averaged across all the trials in each of the two classes defined by the observer responses (more- and less-translucent). The difference pattern between the averaged patterns for the two classes was defined as a "translucency-related pattern". The translucency-related patterns exhibited statistically significant spatial variations, suggesting that the observers judged the translucency of the images more strongly based on particular spatial regions. The images created in the same manner as our composition stimuli based on the translucency-related patterns as composition patterns had smaller global contrasts of non-specular components than the images based on the reversed patterns of the translucency-related patterns, suggesting the relationship between the translucency and global image contrasts. Meanwhile, in the original CG images, the local luminance contrasts in the image regions that were significantly related to the translucency judgment and in the other regions were not significantly different. These results suggest that the observers judged the translucency of the CG images based on their global contrasts of non-specular components, but not on their local contrasts.
Meeting abstract presented at VSS 2012