Laser speckle measuring device and method for measuring in-plane displacement and out-of-plane displacement simultaneously

Abstract

The invention relates to a laser speckle measuring device and a method for measuring in-plane displacement and out-of-plane displacement simultaneously; in the invention, a method that a laser speckle interferometry measuring light path of the in-plane displacement and a laser speckle interferometry measuring light path of the out-of-plane displacement are combined is utilized to realize the measurement of distribution information of the in-plane displacement and the out-of-plane displacement of an object to be measured simultaneously through once light path arrangement. The device and the method in the invention have the characteristics of simplicity in operation, rapidness and accuracy, and can be widely applied to reliable real-time and high-precision measurement for tiny displacement in the field such as opto-electrical nondestructive testing and the like.

Description

technical field [0001] The present invention relates to a laser speckle measurement device and method for measuring tiny displacement, in particular to a device and method for simultaneously measuring in-plane displacement and out-of-plane displacement by using laser speckle. Background technique [0002] Laser speckle refers to the bright and dark spots formed by the interference of scattered light in the imaging space when the laser is irradiated on the rough object. Laser 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 laser speckle measurement method has the advantages of simple optical path, full-field measurement, and non-contact; therefore, it has been widely used in the field of nondestructive testing. After searching the literature, the patent "A device and method for measuring micro-displacement by femtosecond laser speckle correlation method" (authorizati...

AI Technical Summary

Problems solved by technology

After searching the literature, the patent "A device and method for measuring micro-displacement by femtosecond laser speckle correlation method" (authorization number is ZL20061002662.1, authorization date is 2008.04.02), through the two speckle intensity maps before and after the deformation of the object The correlation operation can realize the precision measurement of sub-pixel displacement, but the disadvantage is that this method requires a femtosecond laser system, which is expensive and difficult to maintain, which limits its practical application range; the patent "X-ray speckle device and its micro-displacement Application in measurement" (authorization number ZL200510023203.3, authorization date 2008.07.02), this patent uses X-rays as the light source for speckle testing, which improves the measurement accuracy by 3-4 orders of magnitude compared with visible light, but X-rays are harmful to human health. Harmful, this method is not suitable for popularization, and is only suitable for detection in specific occasions; the patent "portable out-of-plane displacement measuring instrument" (authorization number is ZL200610024418.1, authorization date is 2008.03.12), the device has a compact structure, can measure out-of-plane The characteristics of the displacement; in many cases, the in-plane displacement of the object and the out-of-plane displacement occur at the same time, which loses the information of the in-plane displacement of the object

[0003] The analysis shows that in the existing public literature, in the research of laser speckle measurement method and its application, there is still a lack of devices and methods that have low requirements for test conditions and can simultaneously measure the in-plane displacement and out-of-plane displacement of object deformation.

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