| 摘要 |
PURPOSE:To attain a proper focusing function regardless of the F value, etc. of an image pickup optical system, by using plural image contrast signals obtained from plural image pickup elements, applying a logical to these image contrast signals to obtain a focusing control signal and controllng the lens position with the focusing control signal. CONSTITUTION:A subject image is formed on an image pickup element 21 through an image pickup lens 11 and at the same time projected to two image pickup elements 31 and 41 via a beam splitter 12. The high-pass filters (HPFs) 22, 32 and 42 are connected to three image pickup elements 21, 31 and 41 respectively. The high frequency component amplitude of a video signal varies in response to the image contrast, and each amplitude has the maximum value when the correct focusing is obtained to each image pickup surface. The outputs of the HPFs are led to wave detectors 24, 34 and 44 via gates 23, 33 and 43 respectively, and outputs R, P and Q are obtained in response to maximum values. These outputs are used to operate a controller 50 and then to control the lens 11. |
