| 摘要 |
PURPOSE:To offset fixed pattern noises each other and improve the quality of pictures to be picked up at both dark and light periods by storing the component of a noise signal synchronizing with a horizontal synchronous signal of a picture picked up at a dark period and adding its reversed sigal to the image pickup signal. CONSTITUTION:A video signal A including a noise component 2d is inputted by turing on a switch 4 at a dark period. After only the noise component 2d of the video signal A has been inverted by a phase inverter 6, the video signal is converted into a digital signal and stored in a memory circuit 8. A digital signal of the said stored noise component is converted into an analog signal and inputted always to an adder 10. In case of image pickup at a light period, a switch 5 is turned on and the adder 10 addes a video signal C having a white pattern which is supperposed by a noise component 2d with the same positive pattern as that of the said signal A to a signal B including a reversed phase noise component outputted from the said memory circuit 8, generating a white pattern video signal D having no noise component. |
