An embodiment of an image processing apparatus includes: an illuminating section which sequentially irradiates an object with a first and second illuminating light beams polarized in different directions. The section emits the polarized light beams sequentially so that the wavelength ranges of the light beams do not overlap with each other. The apparatus further includes: a polarization image sensor； a polarization mosaic processing section which obtains a first polarization image while the object is being irradiated with the first illuminating light beam and a second polarization image while the object is being irradiated with the second illuminating light beam； a depressed area detecting section which detects a depressed area on the surface of the object based on the polarization images； and an image forming section which forms an image representing the depressed area in an enhanced form.
