Image compression of background and text tiles
US6594385B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 27, 1998 |
| Grant date | Jul 15, 2003 |
| Priority date | — |
| Expiry date | Oct 27, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/41
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A compression apparatus for compressing a digital image is disclosed and includes a decomposer, a transform encoder unit and a merge plane compressor. The digital image is converted by the compression apparatus into a set of tiles suitable for transform encoding. Each tile from the set is then compressed by converting the tile into a “merge plane data string” and an associated “transform encoded data string”. The merge plane data string describes only the spatial locations of the background pixels in the tile. The transform encoded data describes the tile in the frequency domain but without the spatial frequencies associated with the background pixels. One important use of the present invention is to compress digital images prior to transmitting the digital image to a printer for printing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.