公开(公告)号：US4903134A

公开(公告)日：1990-02-20

申请号：US282394

申请日：1988-12-09

申请人： Hirotsugu Murashima ,  Satoru Maeda ,  Shunji Hirano

发明人： Hirotsugu Murashima ,  Satoru Maeda ,  Shunji Hirano

IPC分类号： H04N5/232

CPC分类号： H04N5/23212

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(公告)号：US4841370A

公开(公告)日：1989-06-20

申请号：US120583

申请日：1987-11-13

申请人： Hirotsugu Murashima ,  Satoru Maeda ,  Shunji Hirano

发明人： Hirotsugu Murashima ,  Satoru Maeda ,  Shunji Hirano

IPC分类号： H04N5/232

CPC分类号： H04N5/23212

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.

摘要翻译： 在摄像机的自动聚焦电路中，通过响应于由图像感测电路（4）获得的视频信号形成的聚焦评估值来执行自动聚焦操作。 第一聚焦电机控制电路（15）控制聚焦电机（3）的旋转，使得聚焦透镜（1）一旦被固定在焦点评估值处于最大值的位置。 第二聚焦电机控制电路（17）将聚焦电机（3）改变预定的非常小的量，以确定焦点评估值的斜率，该改变被重复直到斜率反转，即最大点 被检测到。 结果，聚焦透镜的位置在焦点评估值的最大点被校正。 当校正量超过预定值时，恢复第一聚焦电机控制电路（15）的第一自动聚焦操作。