1. An image processing device comprising: an image acquisition unit configured to acquire image data; a depth information acquisition unit configured to acquire depth information corresponding to depth distribution in a depth direction of the image data acquired by the image acquisition unit; an image transformation unit configured to perform an image transformation process on the image data acquired by the image acquisition unit through coordinate conversion; a depth information transformation unit configured to perform a transformation process on the depth information acquired by the depth information acquisition unit through coordinate conversion corresponding to the coordinate conversion performed on the image data; and an image combination unit configured to combine a plurality of images transformed by the image transformation unit based on the depth information transformed by the depth information transformation unit.