Post-processing method for use in an image signal decoding system
US5787210A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 22, 1995 |
| Grant date | Jul 28, 1998 |
| Priority date | — |
| Expiry date | Sep 22, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N5/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A post-processing method for filtering decoded image signals determines positions of target pixels to be filtered and generates a selection signal indicating whether or not each of the target pixels belongs to a boundary region of a block of decoded image data. In response to the selection signal, each of the target pixel data is selectively filtered through the use of a filtering unit having two filters with different cutoff frequencies. An absolute difference value between filtered and non-filtered target pixel values is compared with a predetermined threshold value. The target pixel value is updated with the filtered target pixel value if the absolute difference value is smaller than the predetermined threshold value; otherwise, a compensated target pixel value is obtained by subtracting the predetermined threshold value from the non-filtered target pixel value or adding the non-filtered target pixel value and the predetermined threshold value, and, then the filtered target pixel value is updated with the compensated target pixel value.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.