Modeling the color image and video quality on liquid crystal displays with backlight dimming

Objective image and video quality metrics focus mostly on the digital representation of the signal. However, the display characteristics are also essential for the overall Quality of Experience (QoE). In this paper, we use a model of a backlight dimming system for Liquid Crystal Display (LCD) and show how the modeled image can be used as an input to quality assessment algorithms. For quality assessment, we propose an image quality metric, based on Peak Signal-to-Noise Ratio (PSNR) computation in the CIE L*a*b* color space. The metric takes luminance reduction, color distortion and loss of uniformity in the resulting image in consideration. Subjective evaluations of images generated using different backlight dimming algorithms and clipping strategies show that the proposed metric estimates the perceived image quality more accurately than conventional PSNR.