A method of classifying pixels in an image is described that includes calculating for each target pixel in the image, a functional value based on a median value of a block of pixels including the target pixel and storing the functional value for each pixel. Pixels in the image are then analyzed to determine if they correspond to edges in the image and if so, are classified as edge pixels. Next the stored functional values are analyzed to define a flat area delimiting function for the image. The stored functional values that do not correspond to edge pixels are then analyzed to define an image detail delimiting function and the non-flat area pixels are classified as being either flat area pixels or detail pixels based on the flat area delimiting function and the detail delimiting function.