In facsimile transmission the sequences of picture elements having the same luminance are transmitted in coded form. The code words have, in general, different lengths and no ambiguous beginning or end marking respectively. Consequently, in case of a disturbance during the transmission not only the luminance...http://www.google.com.au/patents/US4188643?utm_source=gb-gplus-sharePatent US4188643 - Method and arrangement for correcting errors in facsimile transmission
