1. An image processing apparatus comprising: a first interpolating image generating unit configured to interpolate a first image acquired from a plurality of first pixels of a same color having a same sensitivity characteristic based on a signal of the first image, to generate a first interpolating image; a second interpolating image generating unit configured to interpolate a second image acquired from a plurality of second pixels for the same color as the color of the first pixels, having the same sensitivity characteristic as the sensitivity characteristic of the first pixels, by the same exposure as the first pixels based on a signal of the second image, to generate a second interpolating image; a sensitivity characteristic converting unit configured to convert the first and second interpolating images to have a same sensitivity characteristic; and an image synthesizing unit configured to synthesize a synthesized image from the first and second interpolating images converted to have the same sensitivity characteristic by the sensitivity characteristic converting unit.