Method and apparatus for pre-processing mixed raster content planes to improve the quality of a decompressed image and increase document compression ratios
US6272255A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2000 |
| Grant date | Aug 7, 2001 |
| Priority date | — |
| Expiry date | Dec 7, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V30/413
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An improved technique for processing a color or gray scale pixel map representing a document is disclosed. The pixel map is decomposed into a three-plane representation, a reduced-resolution "upper" plane, a reduced-resolution "lower" plane, and a high-resolution binary selector plane. The "upper" and "lower" planes contain the color or gray scale for the page as well as the continuous tone pictures that are contained on the page. The selector plane stores information for selecting from either the foreground plane or background plane during decompression. Information contained in the selector plane is first used to pre-process the upper and lower planes to reduce the amount of data on each of the other two planes that will be subjected to further processing. Each of the pre-processed planes is compressed using a compression technique optimal for the type of data that resides upon it.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.