Facsimile compression for transmission over 800 bit/s to 2400 bit/s digital mobile channels

A technique developed to reduce the transmission requirements of facsimile images while maintaining high intelligibility in mobile communications environments is described. The technique is based on the implementation of a low-cost interface unit suitable for facsimile communication between low-power mobile stations and fixed stations for both point-to-point and point-to-multipoint transmissions. The interface may be colocated with the transmitting facsimile terminal equipment and functions in conjunction with standard Group 3 facsimile terminals. Although the technique was implemented and tested by intercepting facsimile documents in a store-and-forward mode, the algorithms developed operate on a small number of scan lines, thus lending themselves to potential real-time operation over data channel rates ranging from 2400 to 800 b/s, and user-to-interface transmission rates from 9600 to 2400 b/s respectively