1. A method of detecting an opaque image comprising noise identification information in an area of each of a sequence of frames comprising pixels that represent digital video images, the method comprising the steps of: detecting a scene change between at least two of said frames, designated as a current frame and a reference frame; upon detecting the scene change, calculating a stochastic measure σ d of a plurality of pixels in the two frames based on a standard deviation of differences in pixel values in said two frames in a temporal domain; and detecting the opaque image in said area by comparing the stochastic measure σ d with a given noise level.