Method for measuring object deformation by time-domain multi-wavelength heterodyne speckle interference

Abstract

The invention provides a method for measuring object deformation by time-domain multi-wavelength heterodyne speckle interference. The method combines a time-domain speckle interference measurement technology, a heterodyne interference measurement technology and a multi-wavelength measurement technology. Multi-wavelength is introduced for expanding measurement scope; heterodyne is introduced for ensuring measurement precision; and the time-domain technology can directly provide a phase function for a time-varying field. The method has the advantages of simplifying an object deformation detecting system, using two lasers with different central wavelengths, realizing multi-wavelength measurement and expanding the measurement scope.

Description

technical field [0001] The invention relates to the technical field of laser speckle interferometry, in particular to a method for measuring object deformation by time-domain multi-wavelength heterodyne speckle interferometry. Background technique [0002] When the laser is irradiated on an object with a diffuse reflective surface, the high-intensity coherent light diffusely reflected from the surface of the object will interfere to form randomly distributed bright and dark spots, which are named "speckle". Originally, speckle was viewed as a disturbance because it severely affected laser resolution. Therefore, people are trying to reduce the generation of speckle in the use of laser. In the late 1960s, some useful information was found in speckle, and people began to realize that speckle is not only a kind of noise, but also a rare means of random encoding, which can be used to encode and detect the surface. Subsequently, scientists began to study the unique properties of...

AI Technical Summary

Problems solved by technology

[0004] From traditional speckle interferometry to electronic speckle interferometry, digital speckle interferometry and other technologies, two problems cannot be avoided: First, the above technologies only record the two states before and after deformation or displacement, and do not involve time parameters , can not be measured in real time; second, in the case of ensuring the measurement accuracy, the measurement range is limited

This method improves the anti-interference ability of the system to a large extent and improves the measurement accuracy of the system, but it still needs to carry out phase unwrapping (Phase Unwrapping), and the problem of phase ambiguity (Phase ambiguity) still exists, so this method is not effective. extended measuring range

Images