METHOD AND CIRCUIT FOR REDUCING SPARKLE ARTIFACTS WITH LOW-BRIGHTNESS FILTERING

摘要

PURPOSE: A method and circuit for reducing sparkle artifacts with low-brightness filtering is provided to reduce sparkle artifact in a liquid crystal display caused by declination, without degrading high definition sharpness of a final display. CONSTITUTION: A video signal(INPUT X) is decomposed into a higher brightness level signal(HIGH) and a lower brightness level signal(LOW). The threshold between higher and lower brightness levels is adjustable and related to the transition between lower and higher gain portions of the gamma table for an associated liquid crystal display. The lower brightness level signal is low pass filtered(22) to reduce the difference in brightness between adjacent pixels. The higher brightness level signal is delayed in time(24) to match the processing delay through the low pass filter. The delay matched signal and the low pass filtered signal are combined(26) to form a modified video signal(OUTPUT X') less likely to result in sparkle artifacts in the display. Sparkle reduction processing is applied to luminance signals and to video drive signals in various combinations, based on independently selected thresholds.