Computationally efficient brightness compensation and contrast enhancement for transmissive liquid crystal displays

High-quality displays tend to consume significant power in mobile devices. Currently, transmissive liquid crystal displays are among the most common. They are non-emissive and rely on a backlight behind the display panel. Brightness compensation refers to the signal processing technique to adaptively dim the backlight to reduce the power consumption, while increasing the pixel values to preserve the visual quality of the images or even enhance their contrast. Fast computation of the brightness compensation algorithm is essential for practical use. In this paper, we show that a state-of-the-art brightness compensation algorithm, which requires iterations and is computationally demanding, can in fact be solved with a closed-form solution. We also demonstrate with experimental results that we can achieve approximately an 800-fold speedup, while providing effectively identical images to those obtained by the original method.