| 摘要 |
PURPOSE:To eliminate variation in black level by providing an optical shield at part of a solid-state image pickup element, and subtracting a signal from the shield part from a clamped output signal. CONSTITUTION:Plural columns of picture elements of a solid-image pickup element 24 are shielded optically. A component, which corresponds to the optical shield part, of a signal from the element 24 is stored in a memory 21 through a preamplifier 19, a low-pass filter 20, and a clamping circuit 25. A signal during an image pickup period is led through the preamplifier 19, low-pass filter 20 and clamping circuit 25 to a subtracter 23, which subtracts a signal from the memory 21. Thus, the subtracter 23 outputs a video signal free of variation in black level. |
