An image processing method comprises an extracting step for extracting a plurality of images of different depths of a 3-dimensional object, the axes forming different angles with the 3-dimensional object, a binary coding step for eliminating a gray level range of the plurality of images obtained by the extracting step, the gray level range containing a small amount of components of the 3-dimensional object, remapping the other portion 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 the 3-dimensional object based on the plurality of images put in binary form by the binary coding step.