Algorithm Research And Software Design Of Laser Wavenumber Interferometric Scanning

Laser wave-number interferometric scanning technology,as a non-contact out-of-plane measurement technology,has the advantages of non-destructive testing,rapid measurement and large field of view,and still has great development potential.Its measurement technology has a wide range of applications in machinery manufacturing,computer industry,biomedicine,aerospace materials,composite materials testing and other industrial,military and civil fields.Based on the in-depth study of laser wavenumber scanning technology,the phase extraction algorithm of laser wavenumber scanning is improved and the software control system is designed after analyzing and summarizing the laser nondestructive testing technology at home and abroad.The main contents and achievements of this thesis are as follows:(1)Complete the research on the fast phase extraction algorithm of laser wavenumber spectrum,and propose the phase compensation algorithm based on error compensation.In this thesis,the basic theory of laser wave-number scanning interferometry is described firstly,and the two-dimensional Fourier transform is used to extract the change value of current wave-number K in real time for the real-time monitoring of laser wave-number using optical wedge interferometry image.In the interference signal processing,aiming at the slow phase extraction speed compared with the traditional FFT phase extraction algorithm,the phase information is extracted fuzzy by determining the spectrum range of k domain.In order to improve the measurement accuracy,the phase error compensation is obtained by calculating the formula.In this thesis,a fast phase extraction algorithm based on error compensation(FPEAE)is proposed for the first time to improve the calculation rate and phase extraction accuracy of interference signals.(2)The software design of laser wavenumber interferometric scanning measurement system is completed.Software design is divided into laser controller module and computer control module.The laser controller module is programmed based on STM32,combined with the hardware characteristics of the laser controller system,the laser current modulation method and the laser temperature modulation method of linear modulation are designed,and realized by the program.On the computer control end,a set of laser wave-number scanning interferometry software system is designed by combining the basic principle and measurement steps of laser wave-number scanning interferometry technology.The system is compatible with multiple CCD camera industry and laser controllers.Some measurement steps are improved,and some interfaces and commands needed for measurement are given,which is convenient for experimenters to carry out measurement experiments and compare experimental results.(3)The optical wedge interferometry experiment is carried out with the designed program and the results and analysis are given.In the process of laser linear modulation wave number,compared the current modulation and linear temperature modulation degree,and made experiments to verify the stability of the software system,and the test results also surface,using laser interference wave number scanning software system designed by this thesis,the error of temperature modulation RMS below 0.35 ?,the error of the current modulation RMS is lower than 0.5 m A.In the optical wedge interferometry experiment,the efficiency of FPEAE algorithm is 1.6 to 1.8 times faster than FFT phase extraction algorithm,and the measurement accuracy is also improved by 4 to 5 times.