Signal processing of micro displacement measurement based on laser feedback interference system

摘要

The original experimental signal of laser feedback interference system usually has much noise, which mainly consist of high frequency noise and low frequency fluctuation, and cannot reconstruct micro displacement accurately. In order to improve the accuracy of the reconstruction displacement, the original experimental laser feedback interference signal is preprocessed by filtering the noise. Micro displacement is reconstructed by phase-freezing technology after demodulating the preprocessed signal. The experiment results show that the preprocessed signal makes the accuracy of reconstruction displacement in λ/20 resolution. The reconstruction error of fitting is less than λ/20.