Stereo Camera System with Digital Image Correlation Method for Accurate Measurement of Position and Orientation of Positioning Stage

2015 ◽  
Vol 9 (4) ◽  
pp. 436-443 ◽  
Author(s):  
Yusuke Horikawa ◽  
◽  
Akio Mizutani ◽  
Tomoaki Noda ◽  
Hisao Kikuta
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Image Correlation ◽  
Random Errors ◽  
Camera System ◽  
Stereo Camera ◽  
Positioning Stage ◽  
Out Of Plane ◽  
Plane Direction ◽  
Position And Orientation

A stereo camera system with digital image correlation (DIC) was developed for accurate measurement of the position and orientation of a precision positioning stage. Stereo correspondence was carefully calculated by sub-image matching based on the DIC method. Camera parameters for the triangulation were determined from the measurement results ofx,y, andztranslation of an accurate positioning stage. The measured root mean square random errors were 0.6 μm in the in-plane direction and 1.7 μm in the out-of-plane direction. The proportional errors in the in-plane and out-of-plane directions were 0.2 μm/10 mm and 0.5μm/10 mm, respectively.

Optical Strain Monitoring Techniques

2012 ◽  
Author(s):  
Aditya Narayanan ◽  
Andy Morris ◽  
Catrin M. Davies ◽  
John P. Dear
Keyword(s):  
Digital Image Correlation ◽  
Creep Strain ◽  
Digital Image ◽  
Power Plants ◽  
Image Correlation ◽  
Camera System ◽  
Optical Strain ◽  
Point To Point ◽  
The Uk ◽  
And Control

The Auto-Reference Creep Management and Control (ARCMAC) system is being developed as a technique to evaluate the remaining life of power plant components. The system consists of a pair of Inconel plates with a configuration of silicon nitride (SiN) spheres on them, and a camera system used to take images of the gauge during the component’s deformation. The purpose of the system is to measure the creep strain accumulated by a component at regular intervals, tracking the relative motion of the spheres in order to measure a point-to-point value of strain. The system is currently used to capture images of gauges already installed on power plants in the UK as part of scheduled maintenance during plant outages. It is also possible to use the ARCMAC system to capture speckle paint pattern data used in digital image correlation (DIC) in order to visualise the strain field across the heat affected zones (HAZ) in welds and around other strain concentration features. A newer version of the system: the Digital Single Lens Reflex (DSLR) ARCMAC is being developed specifically to capture this kind of data in order to complement the point-to-point strain measurements obtained. This article presents results of experiments performed at room temperature with the purpose of establishing the basic accuracy of the conventional ARCMAC and the DSLR ARCMAC in order to compare their performance. It also intends to evaluate the performance of the latter when used for digital image correlation. The results showcase the accuracy of the technique at high strains using the DSLR camera, showing its usefulness as a tool to measure creep strain.

Self-correction method of out-of-plane motions in two-dimensional digital image correlation

2016 ◽  
Vol 232 (9) ◽  
pp. 1672-1676 ◽  
Author(s):  
Wentao Yan ◽  
Feng Lin
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Correlation Method ◽  
Correction Method ◽  
Image Correlation ◽  
Two Dimensional ◽  
Monitoring Method ◽  
Strain Monitoring ◽  
Out Of Plane ◽  
Relationship Of

Strain monitoring is very important in the manufacturing, assembling, installation and servicing processes in both mechanical and civil engineering fields. Two-dimensional digital image correlation is a simple, efficient strain monitoring method, but one major bottleneck is the unacceptable error due to the unavoidable out-of-plane motions of the object in practice. We propose a “self-correction” method: employing the originally extracted strain values in different directions to correct the errors due to out-of-plane motions. It is applicable to many engineering applications with known relationship of strains in different directions. A uniaxial tension test was conducted to demonstrate the effectiveness and practicality of this self-correction method. Compared with other correction methods, this method is not only simpler but also more efficient in correcting errors due to the lens distortion caused by self-heating. Both the experiment and theoretical analyses demonstrate that this self-correction method maintains the high accuracy of the digital image correlation method.

Error Assessment of Blade Deformation Measurements on a Multi-Megawatt Wind Turbine Based on Digital Image Correlation

2015 ◽  
Author(s):  
Jan Winstroth ◽  
Joerg R. Seume
Keyword(s):  
Digital Image Correlation ◽  
Wind Turbine ◽  
Error Estimation ◽  
Digital Image ◽  
Rotor Blades ◽  
Image Correlation ◽  
Optical Measurements ◽  
Full Field ◽  
Out Of Plane ◽  
Plane Bending

Optical full-field measurement methods such as Digital Image Correlation (DIC) provide a new opportunity for measuring deformation and vibration in wind turbine rotor blades during operation, in high spatial and temporal resolution. Recent field tests on a multi-megawatt wind turbine have demonstrated the vast potential for full scale testing, however little is known about the overall accuracy of DIC measurements on wind turbines. The present work proposes using a virtual 3D wind turbine model for estimating the error associated with the optical measurements. The entire setup is simulated a priori and accurate error estimation becomes possible. The error estimation for a 3.2 MW wind turbine suggests that relative out-of-plane bending of the rotor blades can be measured with an accuracy of ±9.1 mm, relative in-plane bending of the rotor blades can be measured with an accuracy of ±10.2 mm, and relative blade torsion can be measured with an accuracy of ±0.07 deg. This corresponds to a relative error of 0.46% for out-of-plane bending, 1.11% for in-plane bending and 5.46% for blade torsion.

scholarly journals Full-Field Microscale Strain Measurements of a Nitinol Medical Device Using Digital Image Correlation

2020 ◽  
Author(s):  
Kenneth I. Aycock ◽  
Jason D. Weaver ◽  
Harshad M Paranjape ◽  
Karthikeyan Senthilnathan ◽  
Craig Bonsignore ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Computational Models ◽  
Optical Microscope ◽  
Image Correlation ◽  
Full Field ◽  
Physiological Loading ◽  
Out Of Plane ◽  
Computational Modeling And Simulation ◽  
Cantilever Bending

Computational modeling and simulation are commonly used during the development of cardiovascular implants to predict peak strains and strain amplitudes and to estimate the associated durability and fatigue life of these devices. However, simulation validation has historically relied on comparison with surrogate quantities like force and displacement due to barriers to direct strain measurement–most notably, the small spatial scale of these devices. We demonstrate the use of microscale two-dimensional digital image correlation (2D-DIC) to directly characterize full-field surface strains on a nitinol device coupon under emulated physiological loading. Experiments are performed using a digital optical microscope and a custom, temperature-controlled load frame. Following applicable recommendations from the International DIC Society, hardware and environmental heating studies, noise floor analyses, and in- and out-of-plane rigid body translation studies are first performed to characterize the microscale DIC setup. Uniaxial tension experiments are also performed using a polymeric test specimen up to nominal stains of 5%. Sub-millimeter fields of view and sub-micron displacement accuracies (9 nm mean error) are achieved, and systematic (mean) and random (standard deviation) errors in strain are each estimated to be approximately 1,000 μϵ. The system is then demonstrated by acquiring measurements at the root of a 300 μm-wide nitinol device strut undergoing fixed-free cantilever bending motion. Lüders-like transformation bands are observed originating from the tensile side of the strut that spread toward the neutral axis at an angle of approximately 55°. Optical microscale 2D-DIC setups like that demonstrated herein will be useful in future studies for characterizing cardiovascular implant micromechanics, validating computational models, and guiding the development of next-generation material models for simulating superelastic nitinol.

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