Adaptation of Ordering Techniques for Facsimile Pictures with No Single Element Runs
Arun N. Netravali, F. W. Mounts, K. A. Walsh · Bell System Technical Journal · 1979
We present a simple strategy for modification of two-level facsimile pictures and adapt our earlier published ordering techniques to take advantage of the modification. Picture modification consists of eliminating all horizontal runs of “black” or “white” elements which are of length one. For pictures with high resolution (e.g., 200 dots/inch), such a modification does not excessively degrade the picture quality. The resulting entropy of the coded pictures is between 0.018 to 0.115 bits/pel for the eight ccitt pictures, which are scanned and sampled at approximately 200 dots/inch. This amounts to an average reduction of 48 percent compared to one-dimensional run-length coding and 10 percent compared to our previously published best ordering technique.