In an embodiments, an apparatus includes: a polarized light source which sequentially illuminates an object with three or more plane polarized light rays and an image sensor which sequentially captures an image of the object that is being illuminated with each plane polarized light ray and which obtains polarization images by sequentially changing the direction of the polarized light transmission axis at each pixel while the object is being illuminated with each polarized light rays. The apparatus further includes: a processing section for generating an intensity maximizing angle image YPH and a degree of intensity modulation image YD and a distribution estimating section which estimates, based on YPH and YD, the distribution in a single pixel of the azimuth angles of V-grooves on the objects surface.
