An image processing apparatus includes a blending layout information generating unit that generates blending layout information indicative of overlay information in a blended image of plural source images, a source necessity information generating unit that generates source necessity information indicative of unnecessary areas on the source image overwritten by the blending process, a source necessity information storing memory, and a source read masking unit that conducts a read masking control. A process of generating the blending layout information and the source necessity information, and a process of conducting the read masking control are executed in different frame processing periods, separately, to reduce a throughput necessary for generation of the source necessity information.