Tone mapping a high dynamic range (HDR) image is performed by obtaining a log-norm luminance component based on a normalized logarithm of the HDR image. The log-norm luminance component is flattened (tone-compressed) using incrementally-spaced adaptation levels, which are increasingly blurrier representations...http://www.google.com.au/patents/US7433514?utm_source=gb-gplus-sharePatent US7433514 - Tone mapping of high dynamic range images
