Video Recording in High Dynamic Range Scenes

[[abstract]]Recording video in high dynamic range (HDR) scenes usually suffers from the trouble of getting poor contrast videos. In this paper, an integrated signal processing system, which remaps the image to enhance video visibility, is presented. The system extracts pixel local contrasts and nonlinearly stretches the dynamic range of pixel contrast values through histogram equalization. Undesired artifacts in the contrast map are then smoothed by a similar filter, which averages the pixel luminance values only when colors of neighboring pixels are similar to the central one. The luminance value for a pixel is then replaced by the geometric mean of its original value and smoothed contrast value. Finally, the photographic tone reproduction algorithm normalizes pixel values such that the average of log luminance values in the entire video frame is around 18% gray tone. The proposed approach shows better performance in both tone and color reproduction compared with other popular approaches.