1. Apparatus for reducing noise in an input video signal which includes a plurality of video frames, the apparatus comprising: processed frame memory means for storing a noise reduced image; motion estimator means for selecting a target block of image components in said frame memory to be used in calculating a noise reduced video signal; and motion compensated noise reduction means for calculating said noise reduced video signal by calculating a set of time-varying weighted filtering coefficients for the target block and for generating a motion block of noise reduced image components by averaging a plurality of image components in a current block selected from the video signal with respective image components of the target block as weighted by the coefficients.