| 摘要 |
PURPOSE:To discriminate between a binary and mutlilevel image area by comparing the cardinal number of binary information dots appearing in n-number of continuous dots at a sampling point with a clearness parameter for deciding black and white. CONSTITUTION:A discriminating circuit 3 is provided with a counter circuit 31, a clearness parameter circuit 33 and a comparator circuit 32. A binary information signal from a binary information detection circuit 2 counts dots by the counter circuit 31 in synchronizing with a clock circuit 4. The counted result between the n-number of dots up to a current sampling point is supplied to the comparator circuit 32, which compares it with the value of the clearness parameter. When the binary data is larger than the clearness parameter value after their comparison, the current sampling point is decided to lie in the binary area, an the detected information is outputted from an OUT1. When the counted value of the binary data is smaller than the clearness parameter after the comparison, the current sampling point is considered to lie in the multilevel area, whereby the detected information is outputted from the OUT1. Thus the compression ratio of an image data signal can be improved.
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