| 摘要 |
PURPOSE:To obtain an output picture having quite high quality by applying a process fitted respectively for a bit of picture information with single density, and the character mark part of a bit of halftone picture information, when an original consisting of the bit of picture information with single density, and the bit of halftone picture information is read and outputted. CONSTITUTION:A density average value from an average value detection circuit 6f is stored at a variable A, and the maximum output gradation value is divided into five equally, and they are stored at a variable (n). It is decided which (gamma) conversion factor should be selected out of (a), (b), 1, (c), and (d) in a graph, based on which position the density average value stored at the variable A is belonged when the maximum output gradation value is divided into five stages, then the factor being stored at a factor (m), and an output gradation is defined as follows and is outputted, in other words, it is defined as: output gradation value = N X (input gradation value/N)<m>, assuming that d>c>1>b>a>0.
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