| 摘要 |
With the facsimile transmission of pictures the run-lengths (plurality of successive picture elements of the same luminance value) are often transmitted in coded form to save transmission time and transmission bandwidth respectively. Herein the shortest run-length is often allocated to the shortest code word. In accordance with the invention every run-length having the value 1 is either extended to the value 2 or suppressed and the shortest code word is then allocated in a corresponding manner to the run-length 2. As a result the total length of the transmitted code words for a document is considerably reduced. Extension is done such that one picture element is extended to the left to the detriment of the preceding run-length having the opposite luminance value provided this preceding run-length still contains thereafter at least two picture elements and that in the other case one picture element is extended to the right to the detriment of the next run-length provided the latter retains at least the value 2 and that otherwise the run-length having the value 1 is suppressed. It is true that the resolution is slightly reduced, however only for the very thin lines which is fully acceptable and in many cases hardly noticeable.
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