Hybrid technique for reducing blocking and ringing artifacts in low-bit-rate coding
US6950473B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 2002 |
| Grant date | Sep 27, 2005 |
| Priority date | — |
| Expiry date | Mar 17, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/86
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A power-scalable hybrid technique to reduce blocking and ringing artifacts in low bit-rate block-based video coding is employed in connection with a modified decoder structure. Fast inverse motion compensation is applied directly in the compressed domain, so that the transform (e.g., DCT) coefficients of the current frame can be reconstructed from those of the previous frame. The spatial characteristics of each block is calculated from the DCT coefficients, and each block is classified as either low-activity or high-activity. For each low-activity block, its DC coefficient value and the DC coefficient values of the surrounding eight neighbor blocks are exploited to predict low frequency AC coefficients which reflect the original coefficients before quantization in the encoding stage. The predicted AC coefficients are inserted into the low activity blocks where blocking artifacts are most noticeable. Subject to available resources, this may be followed by spatial domain post-processing, in which two kinds of low-pass filters are adaptively applied, on a block-by-block basis, according to the classification of the particular block. Strong low-pass filtering is applied in low-activity…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.