Two-step local dimming for image quality preservation in LCD displays

This paper presents a new approach to local dimming for liquid crystal display (LCD) devices. Local dimming is a very important technique that LCD uses to reduce its power consumption, and is being increasingly adapted in wide display applications. The proposed method determines the backlight luminance level of each block by performing the following two steps. In the first step, it dynamically selects the initial backlight luminance level of each block considering the peak signal-to-noise ratio (PSNR). In the second step, the backlight luminance level of each block is refined by considering the light coming from neighboring blocks and the relations between the current block and its neighboring blocks. In the experiments, the proposed method improves the image quality of the processed images by up to 8 dB in terms of PSNR while consuming less power, when compared to benchmark methods.