FRONT-END SIGNAL PROCESSING METHOD, FRONT-END SIGNAL PROCESSING CIRCUIT, AND IMAGING DEVICE

摘要

PROBLEM TO BE SOLVED: To avoid a phenomenon such as blurring at a boundary between a white part and a black part on an image by enhancing impulse response characteristics, and to avoid formation of a line due to gradation on the image by suppressing the influence of low-band noise causing problems when an output signal of a black level detection control circuit is fed back.;SOLUTION: The output signal of an image sensor 90 having an effective pixel part and an optical black pixel part is input to an inverting input terminal of a correlative double sampling circuit 10, and a fixed DC voltage for black level clamping is superposed on the output voltage of the correlative double sampling circuit 10 from a DC current source 60 having low impedance. Then the black level detection control circuit 50 detects a black level as the signal level of the optical black pixel part from a luminance signal output from the correlative double sampling circuit 10, generates a feedback control voltage for controlling the black level to a predetermined value, and inputs the feedback control voltage to a noninverting input terminal of the correlative double sampling circuit 10.;COPYRIGHT: (C)2009,JPO&INPIT