Non-contact displacement and strain measuring method based on image feature recognition technology

Abstract

The invention provides a non-contact displacement and strain measuring method based on image feature recognition and matching. Experimental equipment and process required by the method are relativelysimple, and in the experimental process, one camera only needs to be used to shoot digital images of a tested material before and after deformation. Natural textures on the surface of the tested material can serve as mark speckles, and if the surface of the tested material is very balanced, the mark speckles can be obtained through a manual speckle making technology. Relatively speaking, a displacement and strain measuring technology based on image processing is simple in calculation and high in feasibility. For the non-contact loss-free measuring method, the textures and characteristics of the material are not lost, obtained data is more accurate, automatic data processing is realized, the change values of a full-field displacement, the width of a material structural member and the like can be obtained, and the environmental requirements are relatively low.

Description

technical field [0001] The invention relates to the field of non-contact displacement strain measurement, in particular to a non-contact displacement strain measurement method based on image feature recognition technology. Background technique [0002] With the development of technology, people have higher and higher requirements for materials, among which the mechanical properties of materials and the bearing capacity of structures are the key to restricting the development of some high-tech. Displacement and strain are the most intuitive responses of materials under stress, and their measurement is also the most important mechanical experimental method for studying the mechanical properties of materials and evaluating the bearing capacity of structures. In the actual measurement, the experimental conditions of relatively harsh and complex environments, such as high temperature and radiation, have a great impact on the measurement and bring great difficulties to the measure...

AI Technical Summary

Problems solved by technology

However, common optical measurement methods, such as speckle method, holographic interferometry, moiré method, CGS method, digital image correlation method, due to the complexity of the measurement optical path, are easily affected by environmental factors, resulting in a decrease in measurement accuracy and poor stability. Strict requirements on the measurement environment

In the digital image correlation method, in a complex environment, the speckle image, grayscale, and brightness of the material will undergo drastic changes before and after deformation, usually accompanied by geometric changes, such as rotation and scaling, which will lead to speckle images. The correlation drops sharply or even disappears, so in a complex environment, the measurement is affected by environmental factors, and the measurement accuracy of the digital image correlation method cannot be guaranteed

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