System and method for segmentation dependent lossy and lossless compression for higher quality
US6198850A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 12, 1998 |
| Grant date | Mar 6, 2001 |
| Priority date | — |
| Expiry date | Jun 12, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/176
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and system takes advantage of both lossy and lossless compression techniques to increase processing speed and efficiency, and to decrease required image storage space. In the system and method, the input image data is divided into pixel blocks. Segmentation tags are used to determine if pixel block contains sharply defined images, such as text or low frequency halftone. If the answer is "no," i.e., a selected or predetermined number of the pixels are not classified as text or low frequency halftone, or the pixels classified as text or low frequency halftone occur only in selected or predetermined areas of the block, then lossy compression is performed on the pixel block. An artificial block is generated and losslessly compressed. The artificial block includes pixels having values that will be losslessly compressed by a large compression ratio. If the answer is "yes," i.e., there are at least the selected or predetermined number of pixels in the pixel block that should be processed as text or low frequency halftone, and/or the pixels classified as text or low frequency halftone do not occur in the selected or predetermined areas of the pixel block, then that block is sent t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.