Image Quality-Aware Backlight Dimming With Color and Detail Enhancement Techniques

Abstract

In this paper, we propose an advanced backlight dimming technique that preserves the quality of color and details in images even when the backlight luminance of liquid crystal display (LCD) devices is lowered. The proposed backlight dimming technique consists of the following two steps: backlight luminance level selection and pixel compensation. In the first step, to reduce power consumption, the proposed approach selects an optimal level of backlight luminance for a given image based on image quality evaluation that considers the peak signal-to-noise ratio (PSNR) and color distortion level. In the second step, it adaptively adjusts the RGB ratio depending on image details, thereby enhancing image color and details, which are degraded by the lowered backlight luminance level calculated in the first step. The simulation results showed that the proposed method successfully selected the optimal backlight luminance level and prevented severe color distortion, while the benchmark method induced severe color distortion in some images. In addition, for the same backlight luminance level, pixel compensation in the proposed method reduced color difference for color distortion evaluation and the loss rate of edge strength, which showed detail loss by up to 3.58% and 40.55%, compared to benchmark methods, respectively.