1. A method of recognizing an image to provide identification thereof, comprising the steps of: storing said image in a picture storage device comprising an array of addressable picture elements each containing numerical data corresponding to levels of light; electronically selecting one or more three-dimensional slopes between selected pairs of addressable fixed locations by subtracting numerical data stored in one or more picture elements at a first fixed location from numerical data stored in one or more picture elements at a second fixed location; comparing said selected slopes with stored slopes previously selected from substantially the same locations of a prior image to determine a correlation therebetween; and providing an identification of recognition based upon the degree of correlation between said selected slopes and said stored slopes.