发明授权
- 专利标题: Automatic focusing circuit for automatically matching focus in response to video signal
- 专利标题(中): 自动对焦电路,用于自动对焦视频信号
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申请号: US120583申请日: 1987-11-13
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公开(公告)号: US4841370A公开(公告)日: 1989-06-20
- 发明人: Hirotsugu Murashima , Satoru Maeda , Shunji Hirano
- 申请人: Hirotsugu Murashima , Satoru Maeda , Shunji Hirano
- 申请人地址: JPX Osaka
- 专利权人: Sanyo Electric Co., Ltd.
- 当前专利权人: Sanyo Electric Co., Ltd.
- 当前专利权人地址: JPX Osaka
- 优先权: JPX61-273212 19861117; JPX61-304411 19861219; JPX62-34763 19870218; JPX62-43405 19870226; JPX62-43406 19870226; JPX62-49513 19870304
- 主分类号: H04N5/232
- IPC分类号: H04N5/232
摘要:
In an automatic focusing circuit of a video camera, automatic focusing operation is performed by a focus evaluating value formed in response to a video signal obtained by an image sensing circuit (4). A first focusing motor control circuit (15) controls the rotation of a focusing motor (3) so that a focusing lens (1) is once fixed in the position where the focus evaluating value takes the maximum value. A second focusing motor control circuit (17) changes the focusing motor (3), by a predetermined very small amount, to determine the slope of the focus evaluating value, which change is repeated until inversion of the slope, that is, the maximal point is detected. As a result, the position of the focusing lens is corrected at the maximal point of the focus evaluating value. When the correction amount exceeds a predetermined value, first automatic focusing operation by the first focusing motor control circuit (15) is resumed.
公开/授权文献
- US5436628A Programmable frequency timing generator with phase adjust 公开/授权日:1995-07-25
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