| 摘要 |
PURPOSE:To eliminate the unnecessary time used for the detection of b2 turning point if coded in the vertical mode, and to shorten the coding time of an original by not executing the decision on the pass mode in case a turning point a1 shown in T.4 of CCITT recommendation exists within the extent of seven picture elements in front and rear of the turning point b1 and executing the coding only in vertical mode. CONSTITUTION:A line to be coded is discriminated whether it is the first one of K pieces of lines, and if so, one-dimensional coding is executed, but in case not the first line, the operation enters the procedure for two-dimentional coding, and a 'EOL+0' representing the two-dimensional coding is attached to the data, a turning point a0 is placed immediately before the first picture element, in order to execute the detection of the turning points a1 and b1. whether the point a1 is within the extent of seven picture elements in front and rear of the b1 exists or not is discriminated; if in, the data is coded in the vertical mode, but if out, the detection of a turning point b2 is executed. Then, whether the point b2 is located on the left of the point a1 or not is judged; if on the left, the data is coded in the pass mode, but if not on the left, the coding is executed in the horizontal mode.
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