| 摘要 |
<p>PROBLEM TO BE SOLVED: To output a video signal having a suitable brightness value even during the time in which an iris is adjusted by a feed-back manner by calculating amplification ratio for having suitable brightness and outputting the video signal by amplifying it at the amplification ratio. SOLUTION: A data sensor 32 senses the brightness of the video signal inputted through the iris 31 and outputs it to a control part 33. The control part 33 inputs the brightness sensed, and preliminarily judges whether the adjustment of the iris is required or not, and in the case that the adjustment of the iris is required, it calculates the amplification ratio making the suitable brightness. The amplification ratio calculated is stored in a buffer part 35. In the case that the adjustment of the iris is required, the control part 33 calculates iris controlled variable, and an iris controlling part 34 adjusts the opening/closing of the iris. On the other hand, in the case that it judges that the adjustment of the iris is not required, the amplification ratio 1 is stored in the buffer part 35. An integrating meter 36 amplifies the video signal by the amplification ratio stored in the buffer part 35 and outputs it.</p> |
