1. A device for the extraction of features of a contour image, which comprises: (a) means for converting a multiplicity of points set at a fixed, very small interval on the contour line consecutively into coordinates in an x-y coordinate system, (b) a first adder for adding the x coordinates of a selected number of points on either side of the first point of said multiplicity of points, (c) a second adder for adding the y coordinates of said selected number of points on either side of said first point, (d) a first divider for dividing each of the two outputs of said first adder by said selected number, (e) a second divider for dividing each of the two outputs of said second adder by said selected number, (f) a first subtractor for subtracting the x coordinates of said first point from the first output of said first divider and subtracting said first output from the second output of said first divider, (g) a second subtractor for subtracting the first output of said second divider from the second output of said second divider and subtracting said first output of the second divider from the y coordinate of said first point, (h) a third divider for dividing the first output of said second subtractor by the second output of said first subtractor, (i) a first multiplier for multiplying the first output of said first subtractor by the output of said third divider, (j) a third adder for adding the output of said first multiplier and the second output of said second subtractor, (k) a first arithmetic means for squaring the output of said third divider, (l) a fourth adder for adding the value "1" to the output of said first arithmetic means, (m) a second arithmetic means for deriving the square root of the output of said fourth adder, (n) a fourth divider for dividing the output of said third adder by the output of said second arithmetic means, and (o) display means for displaying the output of said fourth divider.