1. A computerized method of controlling a quality measure in a compression quality evaluation system, the method comprising: calculating a grain value indicative of an extent of grain present in an input image, said grain value being calculated based on one or more features characterizing a base image related to the input image, wherein said base image is a difference image between the input image and a filtered version of the input image, and wherein said calculating a grain value indicative of an extent of grain present in an input image comprises: applying a Low-Pass-Filter to the input image giving rise to the filtered version of the input image; calculating absolute difference values between corresponding pixels of the input image and the filtered version of the input image giving rise to the difference image; and computing the grain value based on one or more features characterizing the difference image; and configuring the quality measure upon a grain criterion being met by said grain value, the quality measure being indicative of perceptual quality of a compressed image compressed from the input image.