Method for compressing digital documents with control of image quality and compression rate
US6731814B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 2000 |
| Grant date | May 4, 2004 |
| Priority date | — |
| Expiry date | Jul 31, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/41
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for compressing and decompressing electronic documents, with maximum intradocument independence, and maximum flexibility in optimization of compression modes. The method includes receiving documents containing unknown combinations of a plural data types, including combinations of scanned data, computer rendered data, compressed data and/or rendering tags; dividing the received image into strips of blocks determining from the image itself, which data types are present in each block; compressing data of each data type present in each block with a compression method optimized for its data type. Scanned data may be further segmented into plural scanned data types, where each data type is compressed in said compressing data step with a compression method optimized for said scanned image data type. If the received data type is compressed data, the process may include the additional functions of determining a compression ratio thereof, and accepting the compressed data for use as, or decompressing and recompressing the data, based on acceptability of said compression ration determination. An instruction set is generated that allows detailed decompression instruction…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.