Local tone mapping for high dynamic range images
US9437171B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 2013 |
| Grant date | Sep 6, 2016 |
| Priority date | — |
| Expiry date | May 22, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/589
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of local tone mapping of a high dynamic range (HDR) image is provided that includes dividing a luminance image of the HDR image into overlapping blocks and computing a local tone curve for each block, computing a tone mapped value for each pixel of the luminance image as a weighted sum of values computed by applying local tone curves of neighboring blocks to the pixel value, computing a gain for each pixel as a ratio of the tone mapped value to the value of the pixel, and applying the gains to corresponding pixels in the HDR image. A weight for each value is computed based on distance from the pixel to the center point of the block having the local tone curve applied to compute the value and the intensity difference between the value of the pixel and the block mean pixel value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.