| 摘要 |
PROBLEM TO BE SOLVED: To provide an image scanner that enhances the S/N and suppresses the data quantity. SOLUTION: A resolution discrimination means 32 analyzes the spatial frequency of an image represented by an image signal 102A on the basis of the signal from a linear image sensor 10 and decides whether or not high resolution is required, and a reset control circuit 30 controls a reset pulse generating circuit 28 to set the period of a reset pulse 36 supplied to a linear image sensor 12 twice the period of electric charge transfer pulses 22, 24 when the decision result by the resolution decision means 32 denotes negation. Thus, an FD(Floating Diffusion) section 20 of the linear image sensor 12 to which the reset pulse with the double period is supplied stores electric charges for a time longer than the period of the charge transfer pulse and a charge storage section outputs a high voltage for a double updated period.
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