REDUCING SPARKLE ARTIFACTS WITH LOW BRIGHTNESS FILTERING

• Main Authors: WILLIS DONALD HENRY, HAGUE JOHN ALAN
• Format: Patent
• Language: English; Korean
• Published: 14.09.2002
• Edition: 7
• Subjects: ADVERTISING; ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICESUSING STATIC MEANS TO PRESENT VARIABLE INFORMATION; CRYPTOGRAPHY; DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH ISMODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THEDEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY,COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g.SWITCHING, GATING, MODULATING OR DEMODULATING; DISPLAY; EDUCATION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; FREQUENCY-CHANGING; NON-LINEAR OPTICS; OPTICAL ANALOGUE/DIGITAL CONVERTERS; OPTICAL LOGIC ELEMENTS; OPTICS; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; SEALS; TECHNIQUES OR PROCEDURES FOR THE OPERATION THEREOF

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. 비디오 신호(INPUT X)는 고 광도 레벨 신호(HIGH)와 저 광도 레벨 신호(LOW)로 분리된다. 고 광도 레벨과 저 광도 레벨 사이의 임계치(T)는 조정가능하고, 관련된 액정 이미저를 위한 감마 테이블의 고 이득 부분과 저 이득 부분 사이의 전환과 관련된다. 저 광도 레벨 신호는 인접한 픽셀 사이의 광도 차이를 감소시키기 위해서 저역 필터링된다(22). 고 광도 레벨 신호는 저역 필터를 통한 처리 지연에 일치하도록 시간적으로 지연된다(24). 지연이 일치된 신호와 저역 필터링된 신호는 이미저에서 스파클 결함(artifact)을 보다 덜 발생시키도록 변경된 비디오 신호(OUTPUT X')를 형성하기 위해서 결합된다(26). 스파클 감소 처리는, 독립적으로 선택가능한 임계치에 기초하여(도 4), 여러 결합을 통해 휘도 신호와 비디오 구동 신호에 적용될 수 있다.