| 摘要 |
PURPOSE:To measure a wide range of a distance with high accuracy, by arranging a first optical system and a second telecentric optical system parallel to the optical axis of the first optical system so that the focal plane of the first optical system on the rear side thereof coincides with that of the second optical system on the front side thereof. CONSTITUTION:This apparatus is constituted of a first lens 1 having a first optical axis O1 to constitute a first optical system and a second lens 2 having a second optical axis O2 parallel to the optical axis O1 so as to provide a predetermined distance therefrom to constitute a second optical system. Both lenses 1, 2 are arranged so that the focal plane of the lens 1 on the rear side thereof coincides with that of the lens 2 on the front side thereof and an iris 5 having a small opening diameter is provided to the periphery of the front side focus F2 of the lens 2 to bring the lens 2 to a telecentric optical system. Further, an image sensor 4 such as CCD is provided in the vicinity of the rear side focus F2' of the lens 2 so as to cross the optical axes O1, O2 at a right angle. By this constitution, a measuring apparatus is allowed to just oppose to an object point P to be measured and the object point P is positioned on the optical axis O1 and the distance of the image point P' on a sensor 4 of the object point due to the first and second optical systems from the optical axis O2 is detected by the output signal of the sensor 4. This value, the focal distances of both optical systems and the distance R between both optical axes are operated to measure the distance up to the object point P.
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