| 摘要 |
PURPOSE:To always perform optimum focusing control by preventing control speed from becoming different according to the pattern of a video or preventing control from becoming unstable in the moving state of a subject and in the panning or the zooming state of a camera in an autofocusing device for a video camera. CONSTITUTION:The integrating level FV of high frequency component is obtained by an HPF 9, a detection circuit 10 and an integration circuit 11 based on a real luminance signal obtained from a video circuit 7, and the luminance signal is predicted and restored to a signal for a focusing state by an image restoring circuit (or image emphasis circuit) 22, then the integrating level FVx of the high frequency component is obtained by the HPF 23, the detection circuit 24 and the integration circuit 25. The ratio of both levels (FV/FVx) obtained by a divider 26 is set as a focus evaluation value so as to execute the focusing control by a microcomputer circuit 5. The ratio is not influenced by the pattern of the video, thereby always performing the optimum adaptive control. |
