| 摘要 |
PURPOSE:To obtain a picture signal with a superior S/N even when an ambient temperature is high and a shutter time is long, by reading out an image pickup signal for several times separately so that a sum of noise charge and signal charge does not exceed the capacity of a charge accumulation part, and generating the picture signal finally by accumulating the image pickup signal 7 accumulated at every time. CONSTITUTION:When a time T set on a shutter is larger than a prescribed value, the time T is divided by a divisor N(N>=2), and a noise signal being generated before the opening operation of the shutter is accumulated. And after the time T/N of the opening operation of the shutter, a first image pickup signal is fetched, and the noise signal is subtracted from the first image pickup signal, and a subtracted signal is stored in a first memory 11, and furthermore, after the time T/N, a second image pickup signal is fetched, and the noise signal is subtracted from the second image pickup signal. Such operation is repeated for the number(N) of times of division, and after the closing operation of the shutter, the image pickup signal accumulated in the first memory 11 is accumulated in a second memory 12. In such a way, it is possible to obtain a still picture scarcely affected by a dark current.
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