Matched filter processing to improve measuring accuracy of interferometric fringe analysis using a multi-pulse train interferometer

We propose a novel approach to address the problem of measurement accuracy in analyzing the distance between the peak positions of interference envelopes in multi-pulse train (MPT) interferometry. In the frequency domain, a bandpass filter cannot remove all noise since the deterministic signal and noise overlap in the frequency domain. In the proposed method, by focusing on the differences in the statistical properties of deterministic signal and noise, matched filter processing eliminates any uncorrelated noise signals, thereby achieving noise reduction. This paper describes the procedure of the proposed method and its development based on a simple interference fringe model. The proposed approach is introduced within the framework of a MPT interferometer, and the experimental results demonstrate its superiority in determining the distance between peaks over the conventional Fourier transform method. This technique can be useful for high-precision measurement of distances for scientific purposes as well as industrial applications.