A method for accurate extraction of unknown phase shift based on optimized quantum particle swarm optimization

Abstract

The invention relates to a method for accurately extracting an unknown phase shift amount based on an optimized quantum particle swarm algorithm. First, the statistical average value of the Fresnel diffraction field of each phase shift amount in the four-step phase shift is approximately calculated based on the statistical properties of the diffraction field; , obtain the intermediate value according to the phase random condition, and use it to represent the approximate phase shift; finally, set the average error function as the fitness function, and improve the quantum particle swarm algorithm to further approximate the true value of the phase shift, among which, the quantum particle swarm The Gaussian mutation operation is added to the algorithm to make the algorithm conform to the initial distribution law of particles. The invention has reasonable conception and perfect theory, can not only realize the approximate pre-estimation of the unknown phase shift amount in the four-step phase shift, improve the accuracy of the calculation direction, but also improve the accuracy and speed of calculating the real value of the unknown phase shift amount, effectively It overcomes the "sawtooth solution phenomenon" that appears near the true value in traditional iterative methods, and has the advantages of extremely fast speed and excellent solution quality.

Description

technical field [0001] The invention relates to a method for accurately extracting an unknown phase shift amount based on an optimized quantum particle swarm algorithm, belonging to the fields of phase shift interferometry and phase extraction, and is especially suitable for the field of extracting unknown phase shift amounts by an iterative algorithm. Background technique [0002] Optical 3D measurement technology is a non-contact, high-precision projection structured light or natural light surface micro-topography measurement technology, which has been widely used in modern industries such as electronics, automobiles, machining, and textiles. Phase-shifting interferometry (PSI) is an active measurement method in optical 3D measurement technology. It has the advantages of optical 3D measurement technology and has been widely used in various applications from phase measurement to microscope systems. Traditional PSI requires a special and constant phase shift amount (2π / N, N ...

AI Technical Summary

Problems solved by technology

At present, the existing phase shift extraction algorithms can be divided into two categories: iterative algorithm and non-iterative algorithm. The iterative algorithm can be divided into alternating iterative algorithm and progressive iterative algorithm according to the different iterative principles. Both of the iterative methods require the object light wave phase Distribution or multiple iterations between the error function and the phase shift value to gradually approach the accurate phase shift value and the phase distribution of the object light wave, the experimental accuracy is affected by the number of iteration steps, and the calculation time is long, it is difficult to achieve real-time application

The non-iterative algorithm can be divided into the phase shift value solution method based on the statistical characteristics of the phase distribution of the diffraction field, the interferogram extreme value method, and the algebraic fitting method according to the different principles of extracting the phase shift value. Among them, the method based on the statistical characteristics of the phase distribution of the diffraction field The basic basis of the phase shift value solution method is to use the characteristics that the amplitude distribution and phase distribution of the Fresnel diffraction field are independent of each other and the phase distribution of the diffraction field varies approximately randomly. This method will calculate the approximate value of the phase shift. In fact, due to Various practical factors, such as the size of the hologram and the limited number of sampling points, have large errors in the approximate value obtained, and it is necessary to further use an iterative method based on the matching of the interferogram to gradually approach the true value, but , the selection of the phase shift iteration step size has a great influence on the calculation speed: if the step size is too small, the number of iterations needs to be increased to reach the real value; if the step size is too large, it is easy to miss the real value, and the step size needs to be reduced in reverse Looking for, there will be a "sawtooth solution phenomenon" near the true value

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