Method of extracting phase information from multi-wavelength mixed phase shift interferogram

Abstract

The invention discloses a method of extracting phase information from a multi-wavelength mixed phase shift interferogram. The method comprises the following steps: writing one-dimensional data of N interferograms into an interferogram matrix form, wherein each interferogram is a column vector of the interferogram matrix; obtaining a background component matrix of each interferogram; obtaining a covariance matrix from each interferogram matrix; carrying out diagonalizing treatment on each covariance matrix to obtain a diagonalizing covariance matrix; according to the diagonalizing covariance matrixes, obtaining the main components of the interferograms from the interferogram matrixes and the background component matrixes; according to the main components, solving phases of the interferograms through arc tangent functions; and obtaining the phase distribution of an object under synthetic wavelength by virtue of a double-wavelength phase unpacking method. With the adoption of the method, the quantitative phase distribution can be obtained by only needing to use matrix operation, the calculation time needed by an algorithm is less than those needed by most frequency domain algorithms, and simultaneously, the disadvantages of needed time-sharing exposure are avoided.

Description

technical field [0001] The invention relates to the field of optical image processing, more particularly, to a method for extracting phase information from multi-wavelength mixed phase-shift interferograms based on principal component analysis. Background technique [0002] Optical interferometry is a method of recording the information of the object to be measured in the form of light intensity fringes by using the principle of light interference at the wavelength scale of light, and obtaining the phase of the object to be measured by analyzing the interference fringes. In recent decades, the most significant change in various types of instruments is the integration of computers in the measurement systems of the equipment. Interferometry is no exception, and its main performance is the development of PSI (Phase-Shifting Interferometry, phase-shifting interferometry). Phase-shift interferometry is not a specific optical hardware structure, but a data acquisition and data an...

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Problems solved by technology

[0009] The purpose of the present invention is to provide a method for extracting phase information from a multi-wavelength mixed interferogram, aiming to solve the problem that the existing interferometry technology cannot achieve high precision and a large measurable range at the same time at low cost, fast and simple

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