Vibration measurement technology based on the reverse point recognition algorithm for laser self-mixing interference

Abstract

The self-mixing interference (SMI) signal carries the information of the external moving object, which has great physical significance and application prospects for extracting and analyzing the information of the external object. In this paper, we propose a vibration measurement method based on a reverse point recognition algorithm on the SMI laser signal. By extracting and analyzing the hill and valley values of the SMI signal to determine the reverse point, combined with the semifringe counting method, the vibration information of external objects can be accurately extracted. The method we propose simplifies the displacement reconstruction process with high accuracy. The simulation and experimental results show that this method can achieve high-precision measurements of microvibration with an absolute error of less than 19 nm.

Diagnosis of the periodic vibration using laser interferometry

“…Due to the inversion of the displacement, the photocurrent waveform will be reversed at the peaks and valleys of the vibration [8]. Therefore, it is easy to determine the number of fringes between two adjacent reversal points in the photocurrent waveform, and then calculate the vibration amplitude.…”