| 摘要 |
PURPOSE:To prevent variation in black level by optically shielding part of a solid-image pickup element, and deducting a signal from the shielded part from an output signal. CONSTITUTION:A few columns of picture elements of a solid-state image pickup element 24 which are at corresponding positions in the beginning of a horizontal scan and a few rows of picture elements at corresponding positions in the beginning of a vertical scan are shielded optically by a black mask, and a signal from the part is stored in a memory 21. A signal obtained during an image pickup period is led through a preamplifier 19 and a low-pass filter 20 to a subtracter 23, which subtracts the output signal of the memory 21, thus eliminating the black level variation of a video signal. |
