Image processing apparatus

An image processing apparatus comprising:

• a polarized light source which sequentially illuminates an object with three or more kinds of plane polarized light rays, of which the planes of polarization have mutually different angles;
• a polarization image sensor which sequentially captures an image of the object that is being illuminated with each of the three or more kinds of plane polarized light rays and which obtains a plurality of polarization images by sequentially changing the direction of the polarized light transmission axis into three or more different ones at each pixel while the object is being illuminated with each of the three or more kinds of plane polarized light rays;
• a varying intensity processing section which obtains a relation between the angle of the plane of polarization and the intensity value of each pixel based on a pixel signal supplied from the polarization image sensor, thereby generating an intensity maximizing angle image that is defined by the angle of the plane of polarization that maximizes the intensity value with respect to each said pixel and a degree of intensity modulation image that is defined by the ratio of the amplitude of variation in the intensity value caused by the change of the plane of polarization to an average intensity value with respect to each said pixel;
• and
• a distribution estimating section which estimates, based on the intensity maximizing angle image and the degree of intensity modulation image, the distribution in a single pixel of the azimuth angles of V-grooves on the object's surface.