1. An object information processing apparatus for obtaining object information from input image data comprising pixels, comprising: an object determination section for determining whether or not each pixel is a part of an object to be extracted by comparing color information indicating a color of the pixel with a predetermined reference value for the object; and an object information retaining section for retaining coordinate data of the pixel as the object information if the pixel has been determined by the object determination section to be a part of the object to be extracted.