Abstract: The present invention relates to the field of vector quantization of transmitted imagery. In particular, the invention is a method for automatically generating a codebook for use in the transmitter and receiver components of an amplitude-adaptive normalized differential vector quantization system based upon a specified signal-to-noise ratio goal. In accordance with this method, the specified signal-to-noise ratio goal automatically derives the amplitude thresholds and other required data to determine the tradeoff between image quality and data compression for the transmitted imagery.

Abstract: A method for data compression provides for an improved digital facsimile document transmission system. The mixed mode method provides that symbols can be located both individually and as a part of a line of symbols in order to provide for efficient operation for both the symbol and graphic portions of a document to be transmitted without requiring that the symbols be organized in lines or that each location be conveyed independently of all other locations of symbols.