Patent Document ID: 4123778
Application ID: 05748300
Patent Status: 1

Claim One:
1. A method of determining the sharpness of a picture through the detection and evaluation of the absolute values of the density differences between adjoining points of the picture of at least one selected area of the picture, comprising the steps of: (a) determining the absolute values .vertline..DELTA.D.vertline. of the density-differences of a plurality of adjacent image elements within at least one area of a picture; (b) for these absolute values, selecting at least two different threshold values a.sub.1. .. a.sub.n ; (c) comparing the absolute difference values .vertline..DELTA.D.vertline. with each of the threshold values a.sub.1. .. a.sub.n and separately counting those absolute difference values which exceed each of these threshold values to obtain a corresponding number of counts N.sub.1. .. N.sub.n ; (d) comparing each of the obtained counts N.sub.1. .. N.sub.n with a corresponding reference value b.sub.1. .. b.sub.n to produce a decision output for each comparison; and (e) combining the decision outputs of the comparisons to obtain a decision as to the sharpness of the image.