1. An image processing method, comprising: an extracting step for extracting a plurality of images of a 3-dimensional object along one or more axes at different depths, said axes forming different angles with said 3-dimensional object; a binary coding step for eliminating a gray level range containing few components of said 3-dimensional object, remapping the other portion of the gray level range to a predetermined gray level value range, and putting the plurality of images in binary form; and a step for forming a 3-dimensional image of said 3-dimensional object based on the plurality of images put in binary form by said binary coding step.