System and method for enhancement of coded images using adaptive spatial filtering
US5812702A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 22, 1995 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Nov 22, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06T2207/10016
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Pixels in a low bit-rate encoded image are categorized into two or more categories. In one embodiment three pixel categories are used: 1) pixels belonging to quasi-constant (QC) regions where the pixel intensity values vary slowly (e.g., pictorial portions), 2) pixels belonging to textured regions which are characterized by many small edges and thin-line signals (e.g., text portions), and 3) pixels belonging to dominant-edge (DE) regions which are characterized by few sharp and dominant edges (e.g., edge portions). In one embodiment DE pixels are categorized first, then QC and textural pixels are distinguished from the remaining pixels using the number of zero-crossings among the pixels and a threshold. Conventional spatial filters that are well suited for each pixel category type are then used to enhance each region of the image. In one embodiment, various combinations of spatial filters are used to enhance the image.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.