| 摘要 |
PURPOSE:To attain high accuracy (high S/N) and high resolution (multi-bit) by providing a subtractor subtracting a background density data and a multiplier multiplying a reciprocal to an output signal of the subtractor. CONSTITUTION:A digital density signal PD from an A/D converter 7 is inputted to a subtractor 13 and subtracted by a background density data BGD from the 1st correction data memory 11. Thus, a signal PD 1 having a density being the subtraction of the density in reading only other parts of a read object face from the read input density of the read part of the read object face is outputted from the subtractor 13. Then the signal PD 1 is inputted to a multiplier 14, where the signal is multiplied with a data MULD from the 2nd correction data memory 12. Thus, a density signal PD 2 with high accuracy added with a multiple factor and subject to correction of most of density read error caused by uneven lighting of the read part is outputted from the multiplier 14.
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