| 摘要 |
A focus control system for a video camera determines a first gradient indicative of a change in value of a predetermined frequency component in the video signal for first and second positions obtained from the signal of predetermined frequency component in the video signal sampled at the first lens position and at the second lens position, and determines a second gradient indicative of a change in value of the predetermined frequency component in the video signal for second and third lens positions obtained from the signal of the predetermined frequency component in the video signal sampled at the third lens position point, and the speed of longitudinal movement of the lens is controlled in accordance with changes in the first and second gradients, thereby permitting faster focusing and reducing the amount of overrun of the lens during such focusing.
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