1. A method for classifying areas in an image to extract a half-tone area, said method comprising the steps of: for each pixel in said image, performing convolutions of a predetermined size with said each pixel as a center pixel in said convolutions, thereby determine a maximal convolution brightness and a minimal convolution brightness for said pixel; calculating a brightness difference between said maximal and minimal convolution brightnesses of said center pixel; defining the center pixel as a half-tone pixel when said difference is less than or equal to a first predetermined value, said maximal brightness is less than or equal to a second predetermined value and said minimal brightness is greater than or equal to a third predetermined value; counting a number of half-tone pixels within a given area; and defining areas in said image as half-tone areas when said number of half-tone pixels is greater than or equal to a fourth predetermined value.