| 摘要 |
PURPOSE:To suppress an abnormal phenomenon such as blooming or comet tail to a degree not remarkable by adding a voltage detecting a high light signal exceeding a prescribed level to a conventional control signal so as to apply the control also to a signal of an abnomal high light portion. CONSTITUTION:An output signal of a gate circuit 9 is detected by a peak detection circuit 10 and an average value detecting circuit 11, and an output signal of a high light signal detecting circuit 16 is detected by a peak detecting circuit 17 respectively and they are outputted to an output of an adder circuit 20 as a control voltage. In case of the content of image pickup where the contrast ratio among various objects in a pickup screen is almost uniform over the entire screen or a video signal is a prescribed high light detection level Vth or below, an iris circuit and an AGC circuit are controlled by a control voltage only obtained based on the video signal at the screen center portion extracted by a gate circuit 9. If an abnormal high light is generated at the surrounding of the screen, the circuits are controlled for a prescribe rate also with a voltage detecting the high light signal being the Vth or over, and an optimum picture is obtained by suppressing comet tail or blooming. |
