Detecting errors in video images

摘要

PCT No. PCT/GB94/01558 Sec. 371 Date Jan. 18, 1996 Sec. 102(e) Date Jan. 18, 1996 PCT Filed Jul. 19, 1994 PCT Pub. No. WO95/03674 PCT Pub. Date Feb. 2, 1995An error is identified in a video image by calculating frequency-related coefficients for blocks of the image and considering the statistical distribution of said coefficients. The variance of the coefficients is calculated and a block of original image data is concealed if the variance calculated is significantly higher than a stored threshold and/or if said variance calculated is significantly different from variance values derived for similarly positioned blocks within a previous frame. Concealment is effected by selecting image data from a previous frame, displaced in response to transmitted motion vectors.