A method for inspecting flat objects, especially wafers, comprising the steps of scanning a digital image of the object surface; detecting defects on the object surface; generating a binary image of the scanned image where only detected defects are represented; and compressing the binary image; and wherein detected defects are enlarged before compressing by adding additional, adjacent image points to the image points of the defects. It may be advantageous if only defects having a selected size, shape or position are enlarged.