White light scanning interference three-dimensional reconstruction method based on pseudo Wigner-Ville distribution

Abstract

The invention relates to a white light scanning interference three-dimensional reconstruction method based on pseudo Wigner-Ville distribution, and the method comprises the following steps: S1, extracting an interference feature position of a discrete white light interference signal, and obtaining an actual interference signal I (delta z) in actual use; s2, obtaining an analysis form of the actual interference signal I (delta z); S3, analyzing an instantaneous autocorrelation function R (mu, delta z) of the interference signal; s4, acquiring a pseudo Wigner-Ville distribution result WV (delta z, f) taking the spatial position difference mu and the discrete frequency f as a transverse axis and a longitudinal axis; and S5, solving an extreme value position in the direction of the discrete frequency f to obtain an envelope-like signal E (delta z) of the actual interference signal, and extracting a height position of the envelope-like signal. The white light scanning interference three-dimensional reconstruction method provided by the invention is not limited by phase errors and parameter setting, and the obtained envelope information half-width value is relatively small, so that the reconstruction precision is relatively high.

Description

technical field [0001] The invention relates to the field of optical engineering, in particular to a white light scanning interference three-dimensional reconstruction method, in particular to a white light scanning interference three-dimensional reconstruction method based on pseudo Wigner-Ville distribution. Background technique [0002] White light interferometric scanning three-dimensional surface measurement technology is one of the important testing methods for ultra-precision processing industries such as optical processing and micro-electromechanical system (MEMS) manufacturing, as well as semiconductor manufacturing and packaging process inspection. The phase ambiguity problem of single-wavelength interferometry, so white light interferometry plays a very important role in ultra-precision detection technology. [0003] Taking the Michelson-type white light scanning interference system as an example, the basic principle of its measurement is: the light emitted by the...

AI Technical Summary

Problems solved by technology

Frequency domain methods include Fourier transform envelope method, wavelet transform envelope method, spatial frequency domain method and other algorithms that need to be processed by Fourier transform and other methods using frequency domain information. Most of these algorithms have slow calculation speed but low precision The robustness is good. For example, the Fourier transform envelope method needs to undergo a Fourier transform to filter out the negative frequency information, and then perform an inverse Fourier transform to extract the complex envelope distribution of the white light interference signal containing phase information, and then use Phase information or the introduction of Gaussian fitting to accurately extract the most value position, but it is greatly affected by the phase error; the wavelet transform envelope method is similar to the Fourier transform envelope method, which uses the Morlet wavelet function as the transform base, can The complex envelope distribution that reduces most of the noise is extracted, and its reconstruction accuracy is high in most cases, but it is not only affected by the phase noise, but also affected by the parameter settings of the wavelet function, which will lead to more measurement restrictions. It is a little troublesome, and due to the introduction of the wavelet function, it will also cause the envelope signal to widen, which is not conducive to the intensity fitting calculation in some occasions

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