A method for enhancing the contrast of video pictures that includes the
steps of receiving an input video signal; extracting a picture from said
input video signal; determining an active window for said picture;
calculating a histogram for luminance values of pixels in said active
window of said picture; determining characteristics of said histogram;
selecting one suitable mapping function from a plurality of mapping
functions based on the determined characteristics of said histogram; and
mapping the luminance value of each pixel in said picture in accordance
with said selected mapping function.