| In the manufacturing industry,the detection of material quality is one of the important links,and its level directly affects the development of fields of production and life.Non-contact detection technology,especially optical detection technology,as an important means in the field of detection,has a good development prospect.As a way of optical detection,laser wavenumber scanning interferometry has the advantages of high stability,short time consuming,simple operation and strong anti-interference ability.The technology is based on hardware,using software and algorithm to demodulate the collected interference signal,and obtain the off-surface displacement and profile information of the material.The research work and innovation of this paper mainly includes:(1)Doing research on the theory of laser wavenumber scanning and solving the problem of intermittent wave number,(2)Building a laser wavenumber scanning interference system based on two-channels,(3)Verify the availability of the system and the correctness of the theory by experiments.In this paper,The research status and achievements in the field of laser wavenumber scanning interferometry at home and abroad are introduced.Then,based on the basic theory of laser wavenumber scanning interference,the light intensity interference sequence is converted to wavenumber domain.The problems of wavenumber nonlinearity and discontinuity in the experiment are discussed,and the method of on line monitoring wavenumber is proposed.At the same time,the sampling signal is converted to the frequency domain,the random Fourier transform method is used for demodulation analysis,and the formula of spectrum leakage is derived.Then the design idea of the optical path of the whole experimental system is described in detail,and the experimental system is built.The hardware components and software of the system are briefly introduced.Finally,experiments on single wedge,transparent slide and translucent plexiglass are carried out to verify the theory.In this paper,the general experimental steps of the two-channel measurement system are given,and the experimental method,parameter preset and experimental method of the sample are described in detail.Through the sampling of CCD camera and the demodulation of related algorithm,the data are processed and analyzed in detail,and the off-surface displacement and surface profile of the measured sample are measured.The experimental results verify the correctness of the theory and the usability of the system.It can be seen from the experimental results that the laser wavenumber scanning system based on two-channel is the optimization of single-channel scanning system.It strengthens the effective signal of transparent and translucent materials,especially the translucent materials,and has a certain inhibition effect on the interference signal,which is more convenient for the use of this system in actual production.This system has certain practicability.And this system can also accurately measure the off-surface displacement and restore the surface profile of the measured sample,and the error is small,which verifies the correctness of the theoretical knowledge. |
