in which encoding of the length of a succession of picture-elements of the same value along a scanning line is the only encoding step

Full Title

Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof > Bandwidth or redundancy reduction (by scanning H04N1/17 ) > for the transmission or reproduction of two-tone pictures, e.g. black and white pictures > Systems or arrangements allowing the picture to be reproduced without loss or modification of picture-information > in which encoding of the length of a succession of picture-elements of the same value along a scanning line is the only encoding step