| 摘要 |
PROBLEM TO BE SOLVED: To obtain a read image signal of high quality by reducing a difference between odd and even number pixels due to the influence of a noise component to be superposed at the time of executing an analog composition of odd and even number pixels at a high speed in image reading by a CCD and adjusting an image signal level to secure linearity even in an intermediate gradation area. SOLUTION: The odd and even number pixel signals of a white reference board read out by a CCD 32 are processed at fixed gain by an analog processing circuit 50 and the composite signal is A/D-converted by A/D conversion circuits 44 respectively prepared for odd and even number pixels. After the conversion, an odd-even difference detection circuit 48 outputs a phase control instruction to a phase control circuit 49 in accordance with an odd-even difference calculated from the white reference board reading data stared in a digital value detection register 47 and the odd-even difference is corrected by repeating operation for shifting the phase of a sampling clock of the A/D conversion circuits 44 unitl the odd-even difference is included in a target value.
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