Patent ID: 8743378

Claim:
An apparatus for measuring a cylindrically-shaped object, comprising: a measuring head including a support shaft moving vertically with respect to a placement surface on which the object is placed; an inner surface measuring device being held by the measuring head and having three first distance sensors disposed in such a manner that measuring directions are in same plane surface and are radial with respect to a shaft center of the support shaft, the inner surface measuring device measuring distance to a hollow inner surface of the object; an outer surface measuring device being held by the measuring head, and having a second distance sensor disposed in such a manner that measuring direction is in the same plane as the measuring direction of the three first distance sensors and is opposed to any one of the measuring direction of the first distance sensor, for measuring distance from the second distance sensor to an outer surface of the object; a displacement measuring device provided with a third distance sensor for measuring displacement of the measuring head in a height direction of the measuring head; a position calculating means for calculating the center position of the object by calculating a center of circle connecting each of measurement point of the hollow inner surface of the object measured by the three first distance sensors so as to obtain a center of the object; and a shape measuring means for measuring a shape of the object from the center position of the object measured by the position calculating means and results of measurement by the inner surface measuring device, the outer surface measuring device, and the displacement measuring device.