Facsimile compression system
US4091424A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Feb 18, 1977 |
| Grant date | May 23, 1978 |
| Priority date | — |
| Expiry date | Feb 18, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/20
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed herein is a data compression system for compressing binary facsimile data to reduce transmission times over standard telephone system circuits. At the transmit end of the circuit a segment of adjacent scans of, e.g., a white or light background document having, e.g., black typewritten characters or other symbols thereon is stored in a binary format in a buffer memory. A scanner scans the memory to locate the position of a beginning point of each individual character. A block definer circuit then defines a rectangular block closely enclosing the character. A block mapping circuit then scans the block following a predetermined pattern and provides a binary sequence of the black and white portions thereof. A run length encoder may then encode the binary sequence by run length or by Huffman code. A modem connected to the telephone lines sends data corresponding to the location, size and contents of each character block to a receiving modem at the receive end of the telephone circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.