| 摘要 |
PROBLEM TO BE SOLVED: To provide a measuring apparatus, by which when the inside shape of a tunnel H is measured by using an optical distance measuring means, coordinate data which are necessary and sufficient for grasping the inside shape of the tunnel H can be acquired automatically and in as short a time as possible. SOLUTION: A rotary distance-measuring instrument 2 is supported on an automatic rotating stage 3. Pulsed light is projected, so as to be turned around a rotation axial lineβin the horizontal direction. Whenever its projection direction is turned about the rotation axial lineβby a prescribed number of times, the measuring instrument 2 is turned about a vertical axial lineα. While the measuring instrument 2 is turned by an angle range of about 180 deg., distances up to measuring points P are measured in each prescribed period by the measuring instrument 2. Coordinate data on many measuring points P are measured for substantially all directions in the circumference of a measuring device A. Coordinate data on a plurality of measuring target points Pt which are set, so as to keep prescribed intervals on the inside wall of a virtual tunnel medal h are prepared in advance. Only the coordinate data close to the set target points are selected from among the coordinate data on the measuring points P.
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