An image signal processor includes a register and a disparity correction unit. The register stores disparity data obtained from a pattern image data that an image senor generates, and the image sensor includes a plurality of pixels, and each of the pixel includes at least a first photoelectric conversion element and a second photoelectric conversion element. The image sensor generates the pattern image data in response to a pattern image located at a first distance from the image sensor. The disparity correction unit corrects a disparity distortion of an image data based on the disparity data to generate a result image data, and the image senor generates the image data by capturing an object.