Abstract
High Dynamic Range (HDR) tone mapping traditionally extends brightness above a reference white value but uses a fixed floor of zero for black, which maps to a display's minimum luminance setting. This limits creative control over shadow detail by content creators, e.g., the ability to choose blacks deeper than those for which legacy content was mastered or to choose to keep content at a reference black regardless of a display's minimum luminance setting. This disclosure describes a method for extending the HDR tone-mapping range to include negative values, allowing for greater flexibility in tone mapping shadows. In this approach, the normalized pixel value of zero is mapped to a predefined, backward-compatible "reference black." The full brightness capabilities of the hardware are then mapped to an extended range where negative values correspond to luminance levels below this reference black, down to the display's true minimum luminance setting. This technique allows content authors to render deeper black tones while also providing for the preservation of creative intent across displays with different black-level capabilities.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Guyon, Yannis and Gauër, Nathan, "Tone Mapping Using Negative Values to Represent Luminance Below Reference Black", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/9059