. . "A preferred sequence of image processing involves convolving the digitized location parameters from step 1, above, with two 11 by 11 operators, operator 1 being described by the following equation; ##EQU1## and operator 2 being described by the following equation: ##EQU2## where i and j are the operator coordinates, s is a scaling variable, preferably equal to 2, and the resultant image is the mag" . .