Material and shape perception based on two types of intensity gradient information
Fig 2
(a) The image is decomposed into its intrinsic components: albedo, shading, and specular images. Whereas the reflectance image is independent of the shading image, the specular image is dependent on the shading image. This is because the shading intensity is a function of the incident angle of light, while the specular intensity is a function of the incident and viewing angles of the light. (b) The intensities of the shading image within the highlight regions tend to be uniform because both specular and shading intensity depend on the incident angle of light. (c) Intensity gradient maps and the direction maps of the intensity gradient obtained from input images. The magnitude and direction of the vector are indicated as the hue and saturation of a color map, respectively.