| 摘要 |
PURPOSE:To accurately binarize the picture signal, by providing the delay circuit delaying the picture signal by the delay time of LPF and the LPF rejecting high frequency components, using the output of LPF to the binarized threshold level of delay picture and reducing the shading effect. CONSTITUTION:The picture signal VS from the photo electric converter 3 is fed to the LPF7 rejecting the high frequency components D1, D2 and D3, the picture signal VF of low frequency component such as shading rejecting the high frequency components is fed to the adder 8, and the binarized threshold level VTH of the comparator 5 is set with the voltage set unit 6. Further, the picture signal VS converted into electric signal at the converter 3 is fed to the delay circuit 10 delaying the video signal VS by the delay time of LPF7, the delayed picture signal VD is fed to the comparator 5 to reduce the effect such as shading and to correctly perform the binarization of the picture signal VS. |
