| 摘要 |
PROBLEM TO BE SOLVED: To increase a gain while reducing the noise of an image pickup device at the time of low illuminance. SOLUTION: Incident light passed through a lens 1 is converted to video signals in a CCD 2. The video signals sampled in a CDS 3 are inputted to a low illuminance detection circuit 11 and low illuminance signals are outputted in the case that an object is the low illuminance. In an ALC circuit 10, a diaphragm of the lens 1 is controlled. The video signals are passed through an AGC circuit 4 and converted to digital video signals in an A/D conversion circuit 5. In a signal synthesis circuit 6, the three or more pieces of the digital video signals corresponding to vicinity pixels are synthesized and division is performed so as to make the gain larger than 1. In the case that the object is the low illuminance, by the control of a gain increase control circuit 12, the synthesized result of the signal synthesis circuit 6 is outputted. A signal processing is performed in a signal processing circuit 7 and output is performed as the video signals in an encoder circuit 9. At the time of the low illuminance, the noise is reduced and the gain is increased while suppressing the degradation of a resolution.
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