| 摘要 |
PURPOSE:To measure the dimension and shape of, specially, a planar body with high accuracy by combining an ITV camera which has a visual field switching function with a photosensor. CONSTITUTION:The photosensor 3 measures the coordinates of three points which are not on the same line on a measurement plane 20. Then, the whole image of a circular hole 8 is picked up by the ITV camera 51 with a wise visual field. At this time, a three-dimensional driving mechanism 1 and an angle varying mechanism 4 are so driven that the photographic direction S1 is parallel to a normal found by said operation and the distance from the plane 20 is equal to the focal length of the camera 51. Then, three positions of cursor intersections are set almost on a radius of a circle and coordinates based upon a plane coordinate system are measured. The coordinates of the origin of the plane coordinate system on the coordinate system of a measuring instrument are found from the quantities of driving of mechanisms 1 and 4. Those are used to find the coordinates of the three cursor intersections on the coordinate system of a measuring instrument. Similarly, the accurate coordinate values of the three cursor intersections are found by an ITV camera 52 with a narrow visual field, so the center coordinates and radius of a hole 8 on the coordinate system of the measuring instrument are computed from said coordinate values.
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