1. An image processing apparatus comprising: an obtaining unit configured to obtain a scanned image including a plurality of blocks, each of the blocks including a plurality of pixels; a first determination unit configured to determine whether each of the blocks is a color block or a monochrome block; and a second determination unit configured to determine whether the scanned image is a color image or a monochrome image by comparing an arrangement of blocks determined to be color blocks by the first determination unit and a predetermined pattern formed of color blocks and monochrome blocks with each other.