| 主权项 |
1. A vibration displacement measuring method using an electrical signal output from a light sensor, the electrical signal output being generated by overlapping a reference laser beam reflected from a fixed reference side and a laser beam reflected from an object whose vibration displacement is measured, comprising:
a step of discretization, discretizing a cosine signal and a sine signal in the electrical signal output according to index n (n=1, 2, . . . , N); a step of correction, correcting an oval type signal formed by the cosine signal and the sine signal to a circle type signal by using a Heydemann correction method; a step of calculation of relative angle, calculating the relative angle between the n-th index and the n−1-th index by using the corrected cosine signals and corrected sine signals at the n-th index and the n−1-th index; a step of correction and realignment, correcting and realigning the corrected cosine signals and the corrected sine signals at the n-th index and at the n−1-th index by using the relative angle; a step of calculation of phase, calculating a phase at the n-th index by summing the relative angles accumulated from the first index to the n-th index; and a step of calculation of displacement, converting the phase at the n-th index into a vibration displacement at the n-th index. |
