An Optimized Backlight Local Dimming Algorithm for Edge-Lit LED Backlight LCDs

Abstract

This paper presents an efficient optimized backlight local dimming method that minimizes power consumption under a given allowable distortion for liquid crystal displays with edge-lit light-emitting diode backlight. To reduce image quality fluctuation, an inequality constraint optimization problem is formulated using a given allowable distortion and the steepest descent method is used to solve the optimization problem. The experimental results show that the proposed method has better performance than previous methods at the same average power consumption in the unnoticeable level of the difference between the displayed images before and after dimming. Also, the proposed method reduces the risk of large performance degradation and reduces computation time by three times compared with the existing optimization based methods.Index Terms-Light-emitting diode (LED) backlight, light spread function (LSF), liquid crystal display (LCD), local dimming, optimization.

A dual modulation algorithm for accurate reproduction of high dynamic range video

“…Several dual-modulation algorithms for LED/LCD displays have been proposed in the literature [5][6][7][8][9][10][11][12]. Most of these works solve the dual modulation problem using some kind of approximation, e.g., they find LED backlight illumination by taking the maximum, average, or weighted average of pixel values [5,8], or use local block-based approaches [6,7].…”

“…LCD values are generally obtained after the computation of the LED values, by dividing the HDR image luminance by the backlight. Dual modulation can be formulated more rigorously as an optimization problem [9,10,12]. However, these approaches have been mainly targeting low-resolution backlight panels, with tens of LED's, in the context of low-consumption, locally dimmed LCD displays.…”

High dynamic range liquid crystal displays with a mini-LED backlight

“…Therefore, how to achieve HDR is becoming a significant and urgent task for LCD. To overcome this challenge, segmented LEDs are adopted in the LCD backlight unit, where the local zones can be independently dimmed to match the displayed image contents [14][15][16][17][18][19][20]. This so-called local dimming technique can effectively suppress the dark state light leakage and greatly enhance the contrast ratio.…”

“…This so-called local dimming technique can effectively suppress the dark state light leakage and greatly enhance the contrast ratio. Both direct-lit type [5,[14][15][16][17] and edge-lit type [18][19][20] local dimming backlight systems have been developed. Direct-lit type local dimming exhibits better HDR performance, while edge-lit type backlight offers a thinner profile [19,20].…”

High‐performance local‐dimming algorithm based on image characteristic and logarithmic function

“…Recently, many researchers have paid considerable effort to study LED‐backlight local‐dimming algorithms. The simplest ones are the Average method and the Maximum method.…”