Maintaining invalidation information in tiled image representations
US5819278A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 23, 1996 |
| Grant date | Oct 6, 1998 |
| Priority date | — |
| Expiry date | Aug 23, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S707/99942
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for tracking invalidation information in tiled pixel image representations that combines the concept of an invalidation rectangle with the concept of invalid tile flags. A pixel is considered as being possibly invalid if and only if it lies within the invalidation rectangle and the tile containing that pixel is flagged as invalid. In accordance with the present invention, to invalidate an area, the implementing program generates an invalidation rectangle so that it bounds the area and the previous invalidation rectangle (if not empty), and also sets the invalid tile flags in the tiles overlapping that area. To validate an area A within an image, the inventive method performs the following steps: Define area B as the intersection of the area A to be validated with the invalidation rectangle. If area B is empty, the process is done: no pixels in area A are invalid. If area B is not empty, then determine which tiles intersect area B. For each tile intersecting area B, if the tile is marked as valid, and more tiles need to be processed, get the next tile that intersects area B. If all tiles have been processed, the process is done. If a tile is marked invalid, th…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.