Modeling Power-Constrained Optimal Backlight Dimming for Color Displays

Abstract

In this paper, we present a framework for modeling color liquid crystal displays (LCDs) having local light-emitting diode (LED) backlight with dimming capability. The proposed framework includes critical aspects like leakage, clipping, light diffusion and human perception of luminance and allows adjustable penalization of power consumption. Based on the framework, we have designed a set of optimization-based backlight dimming algorithms providing a perceptual optimal balance of clipping and leakage, if necessary. The novel algorithms are compared with several other schemes known from the literature, using both objective measures and subjective assessment. The results show that the novel algorithms provide better quality at a given energy level or lower energy at a given quality level.Index Terms-Backlight dimming, color image, contrast, high dynamic range (HDR), image quality, light-emitting diode (LED) backlight, light leakage, liquid crystal display (LCD), optimization, power saving.

Subjective quality of video sequences rendered on LCD with local backlight dimming at different lighting conditions

“…all LED segments are set uniformly to their full intensity. The second method (the Gradient Descent algorithm 10,11 ), aims at achieving best quality by adapting the backlight to the content according to a display model. Using a gradient descent algorithm, it reaches the best possible quality as evaluated by the display model in terms of MSE.…”

Flicker reduction in LED-LCDs with local backlight

“…The algorithms were Albrecht's algorithm [6], Cho's algorithm [5], Zhang's algorithm [4], Nadernejad's algorithm [1] and the optimization algorithm [2], [11]. For Albrechts algorithm [6], we have implemented the first two steps (out of three, the third one being optional), which produces a clipper-free result.…”

“…For Albrechts algorithm [6], we have implemented the first two steps (out of three, the third one being optional), which produces a clipper-free result. Two versions of the optimization algorithm were implemented [11]. These are based on Gradient Descent (GD) optimization algorithm with two leakage factors (GD with = 0.001, and GD with = 0.0002 [11]).…”

“…Two versions of the optimization algorithm were implemented [11]. These are based on Gradient Descent (GD) optimization algorithm with two leakage factors (GD with = 0.001, and GD with = 0.0002 [11]). All algorithms were simulated on an edge-lit display with 16 backlight segments placed in eight rows and two columns.…”

Subjective comparison of brightness preservation methods for local backlight dimming displays

“…Readers interested in more comprehensive backlight models may refer to the related work in [11][12].…”