Adaptive tone mapping for display enhancement under ambient light using constrained optimization

Abstract We propose adaptive tone mapping for display enhancement under ambient light using constrained optimization. To deal with the visibility reduction caused by ambient light in displays, we perform different operations for display enhancement according to the intensity of ambient light. Since weak ambient light has little effect on displayed images, we only perform contrast enhancement for them. However, strong ambient light makes displayed images dark for human eyes, causing severe visibility reduction in luminance and contrast. To enhance the visibility of displayed images under strong ambient light, we formulate a constraint optimization problem which consists of luminance enhancement, contrast enhancement, and distortion minimization terms, and find an optimal trade-off among them by solving it. Finally, we conduct color scaling to reproduce vivid colors in displayed images. Experimental results demonstrate that the proposed method significantly enhances the brightness, contrast, details, and colors of displayed images and outperforms other state-of-the-art methods under ambient light.