| 摘要 |
PURPOSE:To obtain a video signal processor which extracts a chrominance signal having less noise, specially, having no influence of color mixture in low- illuminance image pickup operation by employing circuit constitution which removes the sine wave term of primary noise and secondary noise and obtains a chrominance signal with reduced color mixture. CONSTITUTION:The chrominance signals SR and SB are processed by a subtracter 10 to obtain (c), which is clipped to the peak-peak value of a noise component by a clipping circuit 11 to obtain a noise signal (d). Further, the noise signal (d) is added to the signal SR by an adder 12 to obtain a signal shown by an equation I . Further, the noise signal (d) is subtracted from the signal SB by a subtracter 13 to obtain a signal shown by an equation II. A red signal SR' and a blue signal SB' have only sine wave terms of primary noise components from the equations I and II to improve an S/N ratio by 3dB, and have no secondary noise component. The chrominance signals SR and SB are summed up by an adder 15 and clipped to a specific level (m) by a clipping circuit 16 to obtain a signal e', which is supplied as a control signal to a nonlinear matrix circuit 14, which outputs chrominance signals SR'' and SB'' by reducing the color mixture of the signals SR' and SB'.
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