Single image-based spatially adaptive dynamic range extension using combined color-channels transmission map

In this paper, a novel dynamic range extension method is presented by detecting under-exposed regions and performing spatially adaptive contrast enhancement. More specifically, a combined color-channels transmission (CCT) map is proposed to detect low-contrast regions, and spatially adaptive gain computation is used to enhance the contrast of the under-exposed regions. As a result, the proposed method can extend the dynamic range of a single input image by changing the brightness of under-exposed regions with preserving the brightness of background. Moreover, the proposed method requires less computational load than existing multiple frames-based high dynamic range (HDR) imaging methods without color distortion. For these reasons, the proposed method can be applied to various imaging devices, such as mobile phone cameras, compact digital cameras, and video surveillance systems.