Method of measuring rotational amount of body having curved surface and direction of rotational axis thereof, apparatus of measuring rotational amount thereof and direction of rotational axis thereof, and method of specifying three-dimensional posture thereof

Abstract

A method of measuring of the present invention includes the steps of photographing a rotating body with the curved surface having marks to obtain two-dimensional images thereof; generating a three-dimensional imaginary body with the curved surface having marks; setting an arbitrary posture of the imaginary body as a reference posture, performing a posture displacement operation in such a way that the marks of the imaginary body are coincident with the marks of the body; specifying a three-dimensional posture of the body on the basis of an amount of the posture displacement operation relative to the reference posture; and determining the rotational amount of the body and the direction of the rotational axis thereof by computing a rotation matrix relating to a rotation operation to make the three-dimensional posture of the body at one time coincident with that at another time.