NTT Research and Development 2008 Review of Activities

Humans can instantaneously sense surface features such as glossiness, translucency and softness. How do humans perceive these material properties? Physically, the material property is a characteristic of surface reflection. To approximate the reflection characteristics from images of surfaces that have complex textures is said to be a very difficult problem. It is therefore thought that the brain brings into play a highly sophisticated information processing mechanism to make such judgments.

However, NTT Laboratories have brought to light the fact that human perception makes use of simple statistical properties of images. For example, when judging surface lightness or glossiness, the brain simply computes skewness in the luminance histogram of the image. The perception of materials may be based on a simple visual mechanism.

NTT Laboratories are searching deeper into the causes of visual characteristics such as the translucency of gelatin, the shininess of metal, and the texture of human skin. We discovered, for example, that simply reversing the light and dark areas in the parts of an image of a glossy surface (shading pattern) other than the highlights causes the surface to be perceived as having a gelatin-like translucency. We are proceeding with the development of techniques for producing dramatic changes in the appearance of image through simple image processing.