Photography Enhancement Based on the Fusion of Tone and Color Mappings in Adaptive Local Region

Existing tone reproduction schemes are generally based on a single image and are, therefore, unable to accurately recover the local details and colors of scene since the limited available information. Accordingly, the proposed tone reproduction system utilizes two images with different exposures (one low and one high) to capture the local detail and color information of low- and high-luminance regions of scene, respectively. The adaptive local region of each pixel is developed in order to appropriately reveal the details and maintain the overall impression of scene. Our system implements the local tone mapping and color mapping based on the adaptive local region by taking the lowly-exposed image as the basis and referencing the information of highly-exposed image. The local tone mapping compresses the luminance range in the image and enhances the local contrast to reveal the details, while the local color mapping maps the precise color information from the highly-exposed image to the lowly-exposed image. Finally, a fusion process is proposed to mix the local tone mapping and local color mapping results to produce the output image. A multiresolution approach is also developed to reduce time cost. The experimental results confirm that the system generates realistic reproductions of HDR scenes.