Gradient based boundary filtering in intra prediction
US11218706B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 2019 |
| Grant date | Jan 4, 2022 |
| Priority date | — |
| Expiry date | Feb 25, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/82
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
After initial intra prediction based on projection along an intra prediction direction, there may exist discontinuities between the predicted block and neighboring blocks. To smooth the block boundary, boundary filtering may be used with intra prediction. In particular, different methods may be used for boundary filtering. The particular filtering method to be used may be selected adaptively based on the intra prediction mode. When gradient-based filtering is selected, the gradient at a reference sample, that is at the same row or column as the current sample, in a reference layer is calculated as the difference between the reference sample and the predicted value for the reference sample using the intra prediction mode. Additional gradient at another reference sample from another reference layer may also be used. Then the initially predicted value for the sample may be adjusted based on the gradient(s) and a decay function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.