Abstract: A pedotopography apparatus which measures the shape of a foot by producing a moire fringe pattern representative of the underside of the foot, capturing and storing an image of the moire fringe pattern in an image storage buffer, analyzing the image to locate at least two points of interest on the foot and computing information corresponding to the distance between the two points. In the preferred embodiment the captured image is processed by Sobel convolution to enhance edges in the image. Both an apparatus and a method of processing are disclosed.