Hardware-efficient image enhancement with bilateral tone adjustment

Various image enhancement methods have been proposed to make image better correlated to human visual perception. In this paper, bilateral tone adjustment (BiTA) is presented to globally enhance the regions with extremely high or low luminance. Different from most curve-based global contrast enhancement methods, proposed BiTA furthermore enhances mid-tone regions that normally contain important scenes. In fact, a general formulation of BiTA is established and two implementation approaches are presented: bilateral gamma adjustment (BiGA) and bilateral polynomial adjustment (BiPA). By the proper parameter setting, the details of the original image will be preserved. Moreover, combined with a simple filter-based local contrast enhancement method, local details can be strengthened without unacceptable noise artifacts. Our enhancement scheme is hardware-efficient since no complex operations are involved, and the simulation shows high-contrast and natural enhancement result.