Effects of head motion and stereo viewing on perceived glossiness.

Many of the previous studies on glossiness perception have focused on glossiness from a single stimulus image. However, the essence of glossiness perception should be the estimation of the surface reflectance properties, which can be estimated computationally from luminance obtained at multiple viewpoints. Thus, the human visual system could also compute glossiness based on retinal images at different eye locations, which are caused by the observer's head motion and stereo viewing. We found that perceived glossiness is strongly enhanced by temporal changes of the retinal image caused by the observer's head motion and image differences between the two eyes in stereo viewing. These findings suggest that the human visual system utilizes rational methods for the perception of surface glossiness. Our data also suggest that the combination of multiple retinal images plays an important role in glossiness perception, just as it is assumed to do in 3D shape perception (i.e., 3D shape perception from binocular disparity and that from motion parallax).