1. A method for detecting a region in a digital image, said method comprising: a) applying a masking condition to a digital image thereby identifying masked pixels that satisfy said masking condition; b) calculating an entropy feature for a pixel-of-interest in a digital image, wherein said calculating comprises: i) forming a first histogram of pixel values for a plurality of pixels in a region surrounding said pixel-of-interest, wherein said masked pixels do not accumulate in said first histogram; and ii) calculating an entropy measure for said first histogram; and c) classifying a neighborhood of said digital image based on said entropy measure and said pixel-of-interest location.