| 摘要 |
PROBLEM TO BE SOLVED: To output both of an absolute value and a difference from a front frame by providing sample and hold circuits respectively holding the signal potential of the former frame of a selected pixel sensor, a reset potential after resetting a detection node and the signal potential of a present frame. SOLUTION: In a reading circuit 20, a signal potential Vc including the noise of the present frame is kept to have a capacity CC by turning on a switch SHC; a signal potential Vp including the noise of the former frame is kept to have a capacity CP by turning on a switch SHP; a reset potential Vr including noise is kept to have a capacity CR by turning on a switch SHR. Then, an absolute value (Vc-Vr) or reduced noise components is measured by turning on a switch SWR and a difference (Vc-Vp) from the former frame of reduced noise component is measured by turning on a switch SWP. However, since an hourly distance is generated, the reset noise of the pixel sensor 10 and the white noise of the circuit 20 cannot be reduced perfectly.
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