Adaptive false contouring prevention in layered coding of images with extended dynamic range
US8873877B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 2012 |
| Grant date | Oct 28, 2014 |
| Priority date | — |
| Expiry date | Nov 1, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/46
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An encoder receives a sequence of images in extended or visual dynamic range (VDR). For each image, a dynamic range compression function and associated parameters are selected to convert the input image into a second image with a lower dynamic range. Using the input image and the second image, a residual image is computed. The input VDR image sequence is coded using a layered codec that uses the second image as a base layer and a residual image that is derived from the input and second images as one or more residual layers. Using the residual image, a false contour detection method (FCD) estimates the number of potential perceptually visible false contours in the decoded VDR image and iteratively adjusts the dynamic range compression parameters to prevent or reduce the number of false contours. Examples that use a uniform dynamic range compression function are also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.