An image processing device comprises: a brilliance gradient computation unit computing a brilliance gradient within an image based on an image information; a color phase value computation unit computing a first color phase value and a second color phase value, the first color phase value representing a color phase inside a candidate region determined based on the brilliance gradient computed by the brilliance gradient computation unit, the second color phase value representing a color phase in a region surrounding the candidate region; and a region extraction unit extracting a region from the candidate region such that a difference between the first color phase value and the second color phase value is less than or equal to a predetermined threshold value.