| 摘要 |
PURPOSE:To correct the sensitivity of one-dimensional image sensor with a simple constitution by extending the counting capacity of a main scanning picture element counter and the main scanning direction memory capacity of a binarization threshold memory circuit up to one main scanning line length and storing the binarization threshold information multiplying with the sensitivity coefficient of the one-dimensional image sensor into a memory circuit. CONSTITUTION:By a main scanning picture element counter 2 and a scanning line counter 3, main scanning position information 13 in one main scanning line and subscanning position information 14 in a dither matrix are given to a binarization threshold memory circuit 4. In the memory circuit 4, as the data of respective addresses equivalent to the scanning position information, the value to multiply a dither threshold level corresponding to a scanning position with a sensitivity coefficient at the main scanning position equivalent to one-dimensional image sensor 1 measured beforehand is stored. An analog digital converter 5 converts an analog output signal 16 of the one-dimensional image sensor 1 to a digital picture signal 17, a digital comparator 6 compares a binarization threshold information signal 15 outputted from the memory circuit 4 with the digital picture signal 17, to output the deciding result as a binary picture signal 18.
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