High dynamic range tone mapping based on Per-Pixel Exposure Mapping

The needs of a realtime vision aid require that it functions immediately, not merely for production of a picture or video record to be viewed later. Therefore the vision system must offer a high dynamic range (often hundreds of millions to one) that functions in real time. In compliment with the existing efficient and real-time HDR compositing algorithms, we propose a novel method for compressing High Dynamic Range (HDR) images by Per-Pixel Exposure Mapping (PPEM). Unlike any existing methods, PPEM only varies exposure to achieve tone mapping. It takes advantage of the camera response to enable exposure synthesis which we call Wyckoff set expansion. The method evaluates the synthetic exposures in a recursive pairwise process to generate a tone mapped HDR image. The results can be approximated using a look-up table, which can be used for real-time HDR applications.