NOISE REDUCTION SYSTEM USING MULTI-FRAME MOTION ESTIMATION, OUTLIER REJECTION AND TRAJECTORY CORRECTION

摘要

A Video signal noise reduction system is disclosed in which image pixels are tracked across multiple frames and then averaged to produce respective noise reduced pixel values. In the disclosed exemplary embodiment of the invention, a motion estimator identifies a motion block within several video frames and determines an approximate velocity vector using a trimmed square estimation procedure. Trajectory correction is applied to each pixel in the motion block based on the velocity vector in order to determine a revised trajectory for the pixels. This correction is accomplished by determining a difference in position of a motion block between successive video frames. Based upon this revised trajectory, appropriate pixels corresponding to the motion block are obtained. These pixels are used in conjunction with pixel values obtained from each of the processed frames to produce an averaged video frame. Each pixel of the averaged video frame replaces the corresponding pixel in the original frame if the difference between the original pixel and the corresponding averaged pixel is less than the median difference between all of the original and averaged pixels.