Patent ID: 7626585

Claim:
An image processing method comprising the steps of: (a) capturing a plurality of images of a subject under an arbitrary illumination condition by a camera through a polarizing element operable to set principal axes of which directions are different from each other, wherein the plurality of images are represented by image data; (b) specifying an incident plane of each pixel of a pixel group in which specular reflection is present in the image data, wherein an incident plane has a direction; (c) computing an incident angle of each pixel of the pixel group in the image data; (d) performing a clustering algorithm on each pixel in the pixel group using a function dependent on both the direction of the incident plane and the incident angle of each pixel thereby forming at least one pixel set, wherein for each pixel the function determines a difference between the incident angle of the pixel and an incident angle corresponding to a center of a cluster, and a difference between the direction of the incident plane of the pixel and a direction of an incident plane corresponding to the center of the cluster, and wherein each pixel set is associated with a different cluster; and (e) performing reflection component separation on the pixel set on an assumption of probabilistic independence between a diffuse reflection component and a specular reflection component to separate intensities of all the pixels thereof into the diffuse reflection component and the specular reflection component; wherein steps (b), (c), (d), and (e) are performed on a processor.