Image noise level estimation from JPEG data
US8090216B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 16, 2008 |
| Grant date | Jan 3, 2012 |
| Priority date | — |
| Expiry date | Nov 3, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/30168
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A system for estimating noise levels in a data stream includes a calculator for determining DC and AC values of DCT coefficients in coded data blocks, where the coded data blocks are within a strip of an image divided into multiple strips. A classifier is included for forming a plurality of luminance levels, based on the calculated DC values. A selector is included for selecting coded data blocks having minimum AC values, as computed by the calculator. At least two coded data blocks are selected for each of the luminance levels. After decoding, another calculator is used for determining a variance for each of the decoded data blocks corresponding to the selected coded data blocks in each strip. An order statistic filter is included for ordering the decoded data blocks in each strip based on the calculated variances. Another selector selects one of the decoded data blocks, for each of the luminance levels.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.