Encoding and transmission method with at least two levels of quality of digital pictures belonging to a sequence of pictures, and corresponding devices
US5196933A · kind A · utility
Assignees
Inventor
Key dates
| Filing date | Mar 19, 1991 |
| Grant date | Mar 23, 1993 |
| Priority date | — |
| Expiry date | Mar 19, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N19/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An encoding and transmission method with at least two levels of quality of digital pictures, each digital picture being formed by at least one matrix of encoded picture elements, wherein each of the pictures is cut up into blocks of picture elements, a reversible mathematical transformation is applied to each of the blocks of picture elements, the coefficients of the transformed picture blocks are quantized and the quantized coefficients are encoded. The transformed coefficients are divided into at least two digital trains, the first train including basic coefficients enabling the reconstruction of a standard quality picture, and at least one second digital train including a set of complementary coefficients enabling the reconstruction of higher quality pictures, in combination with the basic coefficients of the first digital train and possibly the coefficients of other complementary digital trains, the digital trains being processed and/or used distinctly, during the encoding. This enables notably the transmission of digital images that can be received, on the one hand, by moving receivers, especially under difficult reception conditions and, on the other hand, by fixed receivers …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.