| 摘要 |
PURPOSE:To make high-accuracy measurement possible by making a beam incident on a reflecting mirror consisting of a pair of reflecting surface parts from a light source in a prescribed position and reflecting the beam successively on the pair of reflecting surface parts and detecting the positional shift of the reflected beam accompanied with the displacement of an object to be measured by a light receiving position detector. CONSTITUTION:In case that the variation amount in the lapse of time of, for example, a roof is detected, a reflecting mirror 2 is fixed onto a roof 1 as the object to be measured, and a pair of reflecting surfaces 3 of the mirror 2 are provided, for example, at 90 deg.. A laser beam or the like is irradiated from a light source 4 to the reflecting mirror 2, and a light receiving position detector 5 is equipped with an image sensor camera 6 and a screen 7 and is provided near the light source 4. A converter 8 and a recording needle 9 are connected successively to the camera 6. A beam A from the light source 4 is reflected on the reflecting mirror 2 and passes a course B and is picked up by the camera 6. Next, a course (indicated by a dotted line in the figure) C after a time is picked up to detect a variation (c) of the roof 1. |
