High power-saving and fidelity-conserving object-based local dimming for LCD systems with LED-based backlight units

Abstract

A local dimming technique which is enabled on LED-based LCD systems is expected to give more power saving than a global one. However, prior local dimming techniques have not considered human visual system-awareness much as done in an advanced global dimming technique. In this paper, we propose a novel local dimming technique using an object-based approach for both good human visuality and high power saving. It utilizes prevalent colors of individual objects in a given image to do initial dimming, and then enhances the image using a proper fidelity threshold to reduce visible artifacts. Experimental results show that the proposed technique achieves power saving up to 13 and 12 times higher than human visual system-aware global dimming and prior well-designed local dimming techniques, respectively, with a similar human visual system-aware image quality level in a uniform backlight optical profile. It achieves power saving up to 15 and 6 times higher in a Gaussian-based backlight optical profile. Due to a good use of a simpler image fidelity metric, the proposed technique also can make the complexity go lower while keeping a satisfactory image quality.