Patent ID: 6404461
Filing Date: 2002-06-11
Classification: G06T,H04N

Abstract:
Method for detecting static areas in a sequence of digital video pictures comprising the steps of:a) computation of pixel differences between corresponding pixels of consecutive frames or consecutive fields with identical parities; b) accumulation of the magnitudes of the pixel differences over blocks of pixels of the video frames; c) computation of thresholds T(i,j) for pixel blocks, wherein the threshold T(i,j) for each block is adapted to i) an estimated noise level &sgr; for the current field or frame; and ii) to the amount of a block gradient g(i,j), and the threshold levels T(i,j) are calculated according to the formula T(i,j)=N(&agr;&sgr;+&bgr;g(i,j)), â€ƒtherein, N represents the number of pixels within a block and the numbers &agr; and &bgr; are selected dependent on how the estimated noise level &sgr; and block gradient g(i,j) are defined; d) applying the thresholds T(i,j) to the accumulated pixel differences of the corresponding blocks thus providing a preliminary map of static areas; e) modifying the preliminary map of static areas by eliminating isolated static blocks or small groups of adjacent static blocks.