Phase vortex based digital speckle correlation measurement method

A measurement method, vortex technology, applied in the direction of measurement devices, instruments, optical devices, etc., can solve the problems of limiting the practical application range, expensive systems, reducing the accuracy and reliability of digital speckle correlation measurement methods, etc.

Inactive Publication Date: 2011-07-27
HENAN UNIV OF SCI & TECH
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Problems solved by technology

After literature search, the patent "A device and method for measuring micro-displacement by femtosecond laser speckle correlation method" (authorization number is ZL200610026621, authorization date is 2008.04.02), through the correlation calculation of two speckle intensity maps before and after object deformation It can realize the precision measurement of sub-pixel displacement, but the disadvantage is that this method requires a femtosecond laser system. Because the system is expensive and difficult to maintain, its practical application scope is limited; Its Measuring Device" (publication number CN101158679, publication date is 2008.04.09), discloses a method and device for measuring the mechanical properties of trabecular bone using digital speckle correlation method, the patent is digital speckle correlation measurement The new application of the method, without paying attention to the measurement accuracy and precision of the method itself; the patent "a multifunct

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  • Phase vortex based digital speckle correlation measurement method
  • Phase vortex based digital speckle correlation measurement method
  • Phase vortex based digital speckle correlation measurement method

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[0031] According to the structural layout of the accompanying drawings, the measurement optical path diagram is arranged; the continuous wave laser 1 selected is a He-Ne laser, the laser wavelength is 632.8nm, and the power is 25mW. The laser beam emitted by the continuous wave laser 1 becomes parallel light after being collimated by the beam expander 2, and is irradiated on the scatterer 3 to be measured; after the laser beam is scattered by the scatterer 3 to be measured, a speckle light field is formed in the transmission area; Enter the CCD camera 5 for imaging after the converging lens 4, and then store it in the computer 6 for processing;

[0032] First, use the CCD camera 5 to record the speckle field light intensity map I produced before the scatterer 3 to be measured moves. 1 (x, y); when the scatterer 3 to be measured moves slightly, use the CCD camera 5 to record the speckle field light intensity map I generated after the scatterer 3 to be measured moves 2(x, y); i...

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Abstract

The invention discloses a phase vortex based digital speckle correlation measurement method. The method comprises the following steps of: acquiring speckle light intensity images of two states before and after movement of a measured object by using a digital speckle correlation measurement light path; filtering the two images by using a Laguerre-Gaussian complex filter to acquire light intensity complex signals; extracting cross points of real part zero lines and imaginary part zero lines of the signals to acquire phase vortex distribution of the two states before and after the movement of the measured object respectively; calculating corresponding topological charge distribution data matrixes; and finally performing correlation operation on the two data matrixes to acquire displacement information of the measured object. By adopting the method, the influence of background noise and high frequency noise on reliability of correlation measurement can be effectively eliminated, the measurement accuracy can reach a subpixel level; and the method is simple, practicable, quick and accurate and can be widely applied to the fields of nondestructive examination and the like.

Description

technical field [0001] The invention relates to a digital speckle correlation measurement method for measuring tiny displacements. Specifically, it relates to a digital speckle correlation measurement based on phase vortex characteristic parameters to realize the tiny displacement of the measured object. Background technique [0002] Laser speckle refers to the light and dark spots that appear to be chaotic and statistically consistent with the reflection field or transmission field when the laser is irradiated on the surface of a rough object. Speckle carries the information of the measured object, and the change information of the measured object can be obtained by analyzing the speckle field. The digital speckle correlation measurement method was proposed by I.Yamaguchi in Japan and W.H.Peters and W.F.Ranson in the United States in the early 1980s. It is a non-contact optical measurement method for measuring the in-plane displacement of objects; it has an optical path S...

Claims

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Application Information

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IPC IPC(8): G01B11/02
Inventor 李新忠台玉萍杜凯杨传径魏荣慧李立本甄志强陈庆东
Owner HENAN UNIV OF SCI & TECH
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