Parallel reliability-guided algorithm for digital image correlation

2019 ◽  
Vol 61 (12) ◽  
pp. 729-737 ◽  
Author(s):  
Zhe Lin ◽  
Tian Cai ◽  
Yanfeng Wang
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Measurement Accuracy ◽  
Image Sequence ◽  
Image Correlation ◽  
Reference Image ◽  
Measurement Results ◽  
Discontinuous Deformation ◽  
Computing Platforms ◽  
Time Required

Digital image correlation is a non-contact optical method for measuring the displacement and strain on the surface of a material. The existing reliability-guided digital image correlation (RG-DIC) method is stable and reliable for a single image but it still needs a large calculational resource for a sequence of images. Due to the decorrelation effect, the reference image must be replaced several times to correct the measurement results for an image sequence involving a large deformation or a discontinuous deformation. Since the process must be executed sequentially, image by image, the total time required is often unacceptably large when the image sequence is long. The challenge is to find a way of improving the speed while retaining calculational reliability and measurement accuracy, which are important for the practical application of DIC. To address this problem, an improved method is proposed in this paper. The parallel bottleneck caused by the decorrelation effect is solved through improving the parallelism to increase the processing speed. This approach can be used to calculate the strain field of the surface of the material in cases of discontinuous deformation, such as in the area near to a crack. Compared with existing methods, this method not only retains the calculational reliability but also greatly improves calculation speed, especially on current multi-core computing platforms.

scholarly journals DIC (Digital Image Correlation) method in the research of RC beams strengthened with PBO-FRCM materials

2019 ◽  
Vol 97 ◽  
pp. 03008 ◽  
Author(s):  
Dorota Marcinczak ◽  
Tomasz Trapko
Keyword(s):  
Composite Materials ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Gauge ◽  
Concrete Beam ◽  
Correlation Method ◽  
Reinforced Concrete Beam ◽  
Image Correlation ◽  
Strain Gauges ◽  
Reference Image

The article presents tests of a reinforced concrete beam strengthened in a shear with PBO-FRCM composite materials. Measurement of the deformation of the composite was carried out using two methods - with strain gauges and the optical DIC method (Digital Image Correlation). The DIC method consists in taking a series of photographs of the tested object before and during loading. The surface of the tested element must have randomly spaced spots that are applied to the object before measurement. During the study, the cameras monitor the shifting of spots against each other, which in comparison to the reference image before loading gives information about strains and stresses of the tested element. Measurements of deformation of composite materials using strain gauges are difficult to clearly analyse, because the strain gauge is in a specific, limited place, which does not correspond to the work of the entire composite. In addition, the strain gauge tends to break at the place of crack. The article discusses this problem by presenting the results of deformation of PBO-FRCM composite meshes measured in two mentioned ways, their comparison and discussion of results.

Metoda DIC

BUILDER ◽  
2019 ◽  
Vol 259 (2) ◽  
pp. 66-68
Author(s):  
Dorota Marcińczak
Keyword(s):  
Composite Materials ◽  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Gauge ◽  
Concrete Beam ◽  
Correlation Method ◽  
Reinforced Concrete Beam ◽  
Image Correlation ◽  
Strain Gauges ◽  
Reference Image

DIC (DIGITAL IMAGE CORRELATION) METHOD IN THE RESEARCH OF RC BEAMS STRENGTHENED WITH PBOFRCM MATERIALS. The article presents tests of a reinforced concrete beam strengthened in a shear with PBO-FRCM composite materials. Measurement of the deformation of the composite was carried out using two methods - with strain gauges and the optical DIC method (Digital Image Correlation). The DIC method consists in taking a series of photographs of the tested object before and during loading. The surface of the tested element must have randomly spaced spots that are applied to the object before measurement. During the study, the cameras monitor the shifting of spots against each other, which in comparison to the reference image before loading gives information about strains and stresses of the tested element. Measurements of deformation of composite materials using strain gauges are difficult to clearly analyze, because the strain gauge is in a specific, limited place, which does not correspond to the work of the entire composite. In addition, the strain gauge tends to break at the place of crack. The article discusses this problem by presenting the results of deformation of PBO-FRCM composite meshes measured in two mentioned ways, their comparison and discussion of results.

Use of a digital image correlation method for full-field shrinkage measurement in injection molding

2021 ◽  
pp. 030932472110602
Author(s):  
Antoine Dupuis ◽  
Jean-Jacques Pesce ◽  
Jean-Baptiste Marijon ◽  
Stéphane Roux ◽  
Gilles Régnier
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Image Correlation ◽  
Reference Image ◽  
Discharge Process ◽  
Full Field ◽  
Molded Parts ◽  
Geometrical Constraints ◽  
Injection Molded

An original methodology using Digital Image Correlation (DIC) has been designed to precisely measure full-field shrinkages of injection molded polymer plates and then to give the opportunity to compare quantitatively extensive numerical simulations to experiments. The principle of the methodology is based on the full-field strain determination between a reference image of the mold and that of injection-molded parts, which are 275 × 100 × 2.2 mm3 plates. To allow for DIC calculation, 50 µm-depth engravings were machined by electro-discharge process at the surface of the mold. The result of the analysis is a 2D full-field shrinkage map over the whole plate surface (i.e. flow and transverse), with a standard deviation of 0.03%. The marking density has been shown to have a roughly linear influence on the precision of shrinkage measurement. This methodology allows the quantification of the effect of several injection parameters on in-plane shrinkage fields: holding pressure, injection flow rate and direction, geometry of injection gates, or geometrical constraints. Once the best set of parameters of material constitutive laws is identified for the simulation of polymer plates, the simulation procedure is ready to be applied on more complex 3D geometries.

Enhancement of Strain Measurement Accuracy of Two-Dimensional Digital Image Correlation Based on Dual-Reflector Imaging

2019 ◽  
Vol 39 (12) ◽  
pp. 1212002
Author(s):  
朱飞鹏 Zhu Feipeng ◽  
陆润之 Lu Runzhi ◽  
白鹏翔 Bai Pengxiang ◽  
雷冬 Lei Dong
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Measurement ◽  
Measurement Accuracy ◽  
Image Correlation ◽  
Two Dimensional

Deformation Measurement of an Inflatable Reflector Using Digital Image Correlation

2011 ◽  
Vol 66-68 ◽  
pp. 822-826
Author(s):  
Guo Chang Lin ◽  
Hui Feng Tan ◽  
Xiang Hong Bai
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Deformation Behavior ◽  
Image Correlation ◽  
Accuracy Improvement ◽  
Large Space ◽  
Measurement Results ◽  
Random Dot Patterns ◽  
Internal Pressures ◽  
2D And 3D

Inflatable antenna is a potential technique for large space deployable antenna and knowing its reflector’s deformation behavior is quite important for its accuracy improvement. A 1.5m-diameter inflatable reflector’s deformations at different internal pressures are studied using digital image correlation(DIC) in the paper. Because of the symmetry of the reflector, only two representative gores on the reflector are chosen to study. During the digital image correlation measurement, some article random dot patterns are drawn on the reflector’s surface. The 2D and 3D displacement maps of the reflector at different internal pressures are gained by DIC measurement and the cross-section of one gore of the reflector according to the internal pressure are analyzed from the measurement results.

scholarly journals Accurate Measurement of Strain in Noncontact Surface Deformation Using Subset-Based Digital Image Correlation

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
S. Agnes Shifani ◽  
M. S. Godwin Premi
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Surface Deformation ◽  
Computational Cost ◽  
Computation Time ◽  
Image Correlation ◽  
Step Size ◽  
Time Required ◽  
Precision Rate ◽  
Number Of Iterations

The measurement of strain using some contact techniques has some drawbacks like less accuracy and it takes larger computation time for finding each location of subpixels. Thus, a faster noncontact Digital Image Correlation (DIC) mechanism is utilized along with the traditional techniques to measure the strain. The Newton-Raphson (NR) technique is considered to be an accepted mechanism for accurate tracking of different intensity relocation. Generally, the issue regarding the DIC mechanism is its computational cost. In this paper, an interpolation technique is utilized to accomplish a high precision rate and faster image correlation; thereby it reduces the computation time required for finding the matched pixel and viably handles the rehashing relationship process. Hence, the proposed mechanism provides better efficiency along with a reduced number of iterations required for finding the identity. The number of iterations can be reduced using the Sum of Square of Subset Intensity Gradients (SSSIG) method. The evaluation of the projected scheme is tested with different images through various parameters. Finally, the outcome indicates that the projected mechanism takes only a few milliseconds to match the best matching location, whereas the prevailing techniques require 16 seconds for the same operation with the same step size. This demonstrates the effectiveness of the proposed scheme.

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