| 摘要 |
PURPOSE:To improve the accuracy and efficiency of detection by shifting a block to be inputted by one or plural picture elements from a preceding block in accordance with a result whether the block processed immediately before the current one is an edge part or not. CONSTITUTION:Image data from an input device 11 is converted into digital data by a A/D converter 12 and shading correction or the like is executed by a correcting circuit 13. A corrected signal is stored in respective memories 14a, 14b so that block data shifted by plural picture elements in the main scanning direction are stored in the memory 14a and block data shifted by one picture element are held in the memory 14b. A selector 15 outputs a signal 300 when a signal 500 is '1' or a signal 200 when the signal 500 is '0' to an edge detecting circuit 16, the circuit 16 finds out a difference between the maximum value and the minimum value in the block, and when the difference is more than a threshold level, the block is the edge part is decided, and '1' is outputted as a decision signal 500. When the difference is smaller than the threshold level, '0' is outputted. Consequently, the detecting accuracy and efficiency can be improved.
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