Method and apparatus for image data compression and decompression
US4399467A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 13, 1981 |
| Grant date | Aug 16, 1983 |
| Priority date | — |
| Expiry date | Oct 13, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N1/415
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A data compression system which generates several types of symbols from bands of data derived from the digital image. Each group of data bits located in the same bit position across the data band is represented by a mode symbol, which signifies the decimal value of the binary combination of the data contained in that group. The mode symbol is followed by a run symbol, which represents the number of times or incremental positions that the same mode occurs successively until a different mode is generated. Mode and run symbols are transmitted in alternation, with each mode symbol followed by its corresponding run symbol, to an encoder, which generates variable length code words that are transmitted to a receiving station and decoded to provide symbols which are used to form a facsimile image. In one embodiment of this system, the mode and run symbols are combined to form a different type of symbol, known as a ternary octade symbol, to further improve the compression performance of the system.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.