High-precision video extensometer based on a simple dual field-of-view telecentric imaging system

Chen, Bin; Chen, Wenpeng; Pan, Bing

doi:10.1016/j.measurement.2020.108209

Cited by 19 publications

(14 citation statements)

References 27 publications

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“…It is also necessary to use specialized cameras with high resolution and several lighting devices due to the stability of the entire measurement system. To reduce the demands on computing equipment, modifications of DIC correlation have been developed, such as the method of Bin Chen et al [12], which calculate only certain areas of the sample, which speeds up the measurement itself, but on the other hand, loses information about the remaining parts of the sample. Our method does not require any artificial intervention in the sample and performs sample searches only in the initial step and is, therefore, less demanding on computing equipment.…”

Section: Discussionmentioning

confidence: 99%

“…Our primary goal was to create a non-contact system for measuring geometrical properties with an accuracy that is sufficient to evaluate the basic parameters of material sample under tensile testing. The measurement accuracy of our system is discussed in the results section and is in accordance with generally applicable standards in commercially used systems, see [5][6][7][8][9][10][11][12][13][14][15]. The key parameter defining the accuracy of distance measurements is resolution of the camera and the accuracy of its calibration.…”

Section: Proposed System Of Video Extensometrymentioning

confidence: 91%

“…Basic image processing is used in our study, as well as more advanced image processing methods, such as DIC correlation, which will be addressed further in the next chapter [12].…”

Section: Video Extensometrymentioning

confidence: 99%

“…Using recent developments in subpixel registration methods, efforts have been made to utilize DIC in real-time movement and tension monitoring [11]. Basic image processing is used in our study, as well as more advanced image processing methods, such as DIC correlation, which will be addressed further in the next chapter [12].…”

Section: Video Extensometrymentioning

confidence: 99%

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Contactless Material Tensile Testing Using a High-Resolution Camera

2022

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This article deals with the use of contactless measurement with a high-resolution imaging device during tensile testing of materials in a universal tearing machine (UTM). Setting the material parameters in tensile testing is based on changes in the geometrical properties of the sample being tested. In this article, authors propose the method and system for automated measuring the height, width, and crack occurrence during tensile testing. The system is also able to predict the location of crack occurrence. The proposed method is based on selected algorithms of image analysis, feature extraction, and template matching. Our video extensometry, working with common inspection cameras operating in visible range, can be an alternative method to expensive laser extensometry machines. The motivation of our work was to develop an automated measurement system for use in a UTM.

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Section: Discussionmentioning

confidence: 99%

Section: Proposed System Of Video Extensometrymentioning

confidence: 91%

“…Basic image processing is used in our study, as well as more advanced image processing methods, such as DIC correlation, which will be addressed further in the next chapter [12].…”

Section: Video Extensometrymentioning

confidence: 99%

Section: Video Extensometrymentioning

confidence: 99%

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Contactless Material Tensile Testing Using a High-Resolution Camera

2022

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“…Their research group also presented a novel dual FOV telecentric imaging system, where the strain resolution was increased by extending the gauge length. 10,11 Clear silhouette images of the target outline can be captured by combining a camera with a telecentric lens and telecentric illumination. Theoretically, this optical system can resist ambient lighting because the camera receives only collimated light through the telecentric lens, thus facilitating image quality maintenance under various situations.…”

Section: Introductionmentioning

confidence: 99%

Video extensometer for structural steel using silhouette image from telecentric illumination system

Teranishi

2022

Opt. Eng.

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. Steel structures experience plastic deformation and damage during large earthquakes. The stress–strain (S–S) curve of structural steel can be used to develop a constitutive model to simulate its structural behavior. The S–S curve can be obtained by video extensometers, the efficiency of which with a telecentric lens and telecentric illumination remains unclear. The applicability of a telecentric lens and telecentric illumination system to video extensometers were investigated. Rigid-body motion and tensile testing were performed and the carrier of displacement of six gauge lengths was traced. Further, N images were obtained under a constant displacement/force and averaged to reduce the pseudo strain. Experimental results showed that the pseudo strain increases with the out-of-plane rigid displacement but remains unaffected by the in-plane rigid-body displacement. Tensile testing results showed an error difference of <10 % for the Young’s modulus obtained from the video extensometer and strain gauge.

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