发明授权
- 专利标题: Automatic focusing circuit using a two period detection interval to compensate for motion occurring within a field of view
- 专利标题(中): 使用两个周期检测间隔的自动聚焦电路来补偿在视场内发生的运动
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申请号: US155901申请日: 1988-02-16
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公开(公告)号: US4853789A公开(公告)日: 1989-08-01
- 发明人: Hirotsugu Murashima , Satoru Maeda
- 申请人: Hirotsugu Murashima , Satoru Maeda
- 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: JPX62-34767 19870218
- 主分类号: G02B7/28
- IPC分类号: G02B7/28 ; H04N5/232
摘要:
In an automatic focusing circuit of a video camera, an automatic focusing operation is performed by a focus evaluating value produced in response to a video signal obtained in an image sensing circuit (4). A focusing motor control circuit (14) controls 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. Then, a control circuit (14) resumes the automatic focusing operation after a lapse of a second time period when it is determined that the focus evaluating value was decreased to a predetermined level during a first time period and maintained the level over the second time period, and does not resume the automatic focusing operation when it is determined that the focus evaluating value did not maintain the level. On the other hand, the control circuit (14) resumes the automatic focusing operation after a lapse of the first time period when it is determined that a time period which is more than the first time period is required until the focus evaluating value attains the predetermined level.
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