Patent US 3,935,379

The transmission requirements for digital information representing images, such as radar displays produced by radar video returns and business letters, are reduced by encoding successive sets of duplicate data in the form of N-bit words which represent the data, each suffixed by an M-bit portion of a K-bit word representing the number of duplicate N-bit words. The output words, consisting of the M and N bit portions, are generated until all non-zero portions of the K-bit words are accounted for. The number of output words adapt to the run length of duplicate data words and provide for data compression; thus reducing transmission bandwidth requirements.