To encode a binarized image at a high efficiency through a run length coding.
A conversion pattern of a block, consisting of 2×2 pixels where black or white pixels are consecutive in a line direction for run length coding, is prepared for a table 8, and a natural still image received from an input means 1 is binarized by a binarization means 4 and blocks each consisting of 2×2 pixels in the binary images obtained are replaced with conversion patterns, stored in the table 8 by a pattern conversion means 4. Then binary image data subject to replacement processing are run-length-coded by the MH coding and sent as G3 facsimile data from communication means 6, 7. That is, a block in the binary image is replaced with the conversion pattern, to extend the run length of the black pixel or white pixel, and the code length as a result of applying run length coding to the binary image is reduced band the data amount is reduced.
TERANISHI ISAO
YAMAMOTO KAZUHIRO
