1. An image processing apparatus, comprising: a first selection unit selecting a first pixel group including at least one pixel from an input color image; a second selection unit selecting a second pixel group including at least one pixel corresponding to each of the at least one pixel included in the first pixel group from an input depth image; a calculation unit calculating a transformation function of the first pixel group and second pixel group based on a coordinate value of each of the at least one pixel included in the first pixel group and a coordinate value of each of the at least one pixel included in the second pixel group; and an image matching unit matching each pixel of the input color image with each pixel of the input depth image based on the transformation function.