1. An image processing apparatus comprising: a determination unit that determines whether contrast enhancement processing should be performed on an input image; an intensity mapping unit that generates a plurality of images having different exposure times from the input image, using intensity mapping, if the contrast enhancement processing should be performed on the input image; and an image composition unit comprising a processor for composing the plurality of images into an image, if the contrast enhancement processing should be performed on the input image, wherein the determination unit segments the input image in block units, assigns a weight to each block according to the location of each block, and calculates an average brightness value of the input