1. An object classification system comprising: means for storing discriminator quantities related to certain surface characteristics of previously classified objects; a sensor which provides a signal which varies relative to surface characteristics of a detected object as said sensor moves with respect to the detected object; calculating means, responsive to the varying signal from the sensor, for calculating a plurality of discriminator quantities related to surface characteristics of the detected object including the mean of the varying signal and the number of excursions above one standard deviation from the mean; and means for matching the calculated discriminator quantities with the stored discriminator quantities for classifying the detected object.