A color local dimming algorithm for liquid crystals displays using color light emitting diode backlight systems

Abstract

A color local dimming algorithm is proposed to reduce the image distortion and power consumption of liquid crystal displays (LCDs) by using color light emitting diode (LED) backlights. The proposed algorithm is demonstrated using a 55-in. LCD panel with a RGB LED backlight system. In the proposed algorithm, the dimming rate of local blocks is determined by calculating the image distortion of the dimming image, and this is used to achieve steady image quality. The image data of the LCD panel are modified to reduce color distortion by removing the differences in chromaticity. Simulated test results show that the average, standard deviation, and relative variation of PSNRs for the test video are 43.74 dB, 3.57 dB, and 0.082, respectively. The average color differences using the proposed algorithm are 9.6, 5.0, 5.6, and 4.2 for the test patterns with 2 x 2,4 x 2,4 x 4, and 8 x 4 white boxes, respectively. The measured average power saving ratio for the test video is 67.3%. (C) 2012 Elsevier Ltd. All rights reserved.