REDUCING SPARKLE ARTIFACTS WITH LOW BRIGHTNESS PROCESSING

• 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: Reducing sparkle artifacts using low-brightness image processing is provided to reduce sparkle artifacts in an LCOS(Liquid Crystal On Silicon) imager caused by declination. CONSTITUTION: A method for reducing sparkle artifacts in a liquid crystal imager comprises the steps of low pass-filtering only a first lower brightness level signal component of a video signal, and slew rate-limiting only a second lower brightness level signal component of the video signal having the low pass filtered signal component. The video signal has the low pass filtered and the slew rate limited signal components less likely to result in sparkle artifacts in the imager. Brightness thresholds for defining the lower brightness level signal components and slew rate limits are selected in accordance with transitions between lower and higher level gain portions of a gamma table associated with the imager, for example an LCOS imager. 액정 이미저(liquid crystal imager) 내의 섬광결함(sparkle artifacts)을 감소시키기 위한 방법은 : 비디오 신호의 제 1 낮은 밝기 레벨 신호성분만을 저역통과 필터링하는 단계; 및 상기 저역통과 필터링된 신호성분을 가지는 상기 비디오 신호의 제 2 낮은 밝기 레벨 신호성분만을 경사도(slew rate) 제한하는 단계를 포함하며, 여기서 상기 저역 통과된 신호성분 및 상기 경사도 제한된 신호성분을 가지는 상기 비디오 신호는 상기 이미저 내에 섬광결함이 나타나는 결과를 가져올 가능성이 더 적다. 상기 낮은 밝기 레벨 신호성분들에 대한 서로 다른 밝기 문턱값들 및 경사도 한계들이 상기 이미저, 예컨대 LCOS 이미저와 연관된 감마표의 낮은 및 높은 레벨 이득 부분 사이의 전이에 따라 선택될 수 있다.