| 摘要 |
PURPOSE:To prevent a coloring by a spurious color signal generating in a horizontal outline section of an image by detecting a horizontal direction outline from a luminance signal and controlling a suitable quantity of gains of an NTSC carrier chrominance signal and color difference components or the like in a gain control circuit. CONSTITUTION:When an image having both sides of black is picked up by a video camera, a signal wave form of 1 horizontal scanning cycle of a wide band luminance signal YH at an output end of a low pass filter 3 becomes a wave form as shown in Fig. (a). This signal of YH is taken out as a primary differential wave form as shown in a figure (b) at the output end of a high pass filter 9 and further the signal of the primary differential wave form is rectified by both waves by a detecting circuit 10 to have a signal detecting a horizontal outline section is shown in the figure (c). The detected signal is made as a control signal of gain control circuits 11, 12, 13 and suitable quantities of the gains of YL, R, B are respectively controlled, thereby a desired quantity of the spurious color signal at the horizontal outline section can be restricted.
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