METHOD AND CIRCUIT FOR REDUCING SPARKLE ARTIFACTS WITH LOW BRIGHTNESS FILTERING

摘要

PROBLEM TO BE SOLVED: To provide a method for decomposing a video signal (INPUT X) into a higher brightness level signal (HIGH) and a lower brightness level signal (LOW). SOLUTION: A threshold (T) between the higher brightness level signal and the lower brightness level signal is adjustable. The lower brightness level signal is low-pass filtered (in 22) so as to reduce the difference in brightness between adjacent pixels. The higher brightness level signal is delayed in time (in 24) so as to match the processing delay through the low-pass filter. The delay matched signal and the low-pass filtered signal are combined (in 26) so as to form a modified video signal (OUTPUT X') less likely to result in sparkle artifacts in the imager. The sparkle reduction processing can be applied to luminance signals and to video drive signals in various combinations on the basis of independently selectable thresholds.