scholarly journals py2DIC: A New Free and Open Source Software for Displacement and Strain Measurements in the Field of Experimental Mechanics

Sensors ◽  
2019 ◽  
Vol 19 (18) ◽  
pp. 3832 ◽  
Author(s):  
Valeria Belloni ◽  
Roberta Ravanelli ◽  
Andrea Nascetti ◽  
Martina Di Rita ◽  
Domitilla Mattei ◽  
...  
Keyword(s):  
Open Source ◽  
Template Matching ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Memory Storage ◽  
Image Correlation ◽  
Digital Cameras ◽  
Software Packages ◽  
Pros And Cons ◽  
University Of Rome

Thanks to the advances in computer power, memory storage and the availability of low-cost and high resolution digital cameras, Digital Image Correlation (DIC) is currently one of the most used optical and non-contact techniques for measuring material deformations. A free and open source 2D DIC software, named py2DIC, was developed at the Geodesy and Geomatics Division of the Sapienza University of Rome. Implemented in Python, the software is based on the template matching method and computes the 2D displacements and strains of samples subjected to mechanical loading. In this work, the potentialities of py2DIC were evaluated by processing two different sets of experimental data and comparing the results with other three well known DIC software packages Ncorr, Vic-2D and DICe. Moreover, an accuracy assessment was performed comparing the results with the values independently measured by a strain gauge fixed on one of the samples. The results demonstrate the possibility of successfully characterizing the deformation mechanism of the investigated materials, highlighting the pros and cons of each software package.

scholarly journals A NEW DIGITAL IMAGE CORRELATION SOFTWARE FOR DISPLACEMENTS FIELD MEASUREMENT IN STRUCTURAL APPLICATIONS

2017 ◽  
Vol XLII-4/W2 ◽  
pp. 139-145 ◽  
Author(s):  
R. Ravanelli ◽  
A. Nascetti ◽  
M. Di Rita ◽  
V. Belloni ◽  
D. Mattei ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Template Matching ◽  
Structural Engineering ◽  
Testing Machine ◽  
Memory Storage ◽  
Image Correlation ◽  
Full Field ◽  
Structural Applications ◽  
University Of Rome

Recently, there has been a growing interest in studying non-contact techniques for strain and displacement measurement. Within photogrammetry, Digital Image Correlation (DIC) has received particular attention thanks to the recent advances in the field of lowcost, high resolution digital cameras, computer power and memory storage. DIC is indeed an optical technique able to measure full field displacements and strain by comparing digital images of the surface of a material sample at different stages of deformation and thus can play a major role in structural monitoring applications. <br><br> For all these reasons, a free and open source 2D DIC software, named py2DIC, was developed at the Geodesy and Geomatics Division of DICEA, University of Rome <q>La Sapienza</q>. Completely written in python, the software is based on the template matching method and computes the displacement and strain fields. The potentialities of Py2DIC were evaluated by processing the images captured during a tensile test performed in the Lab of Structural Engineering, where three different Glass Fiber Reinforced Polymer samples were subjected to a controlled tension by means of a universal testing machine. <br><br> The results, compared with the values independently measured by several strain gauges fixed on the samples, demonstrate the possibility to successfully characterize the deformation mechanism of the investigated material. Py2DIC is indeed able to highlight displacements at few microns level, in reasonable agreement with the reference, both in terms of displacements (again, at few microns in the average) and Poisson’s module.

Rapid mapping accuracy assessment using low-cost UAV and open-source Structure from Motion

2020 ◽  
Vol 52 ◽  
pp. 55-61
Author(s):  
Ettore Potente ◽  
Cosimo Cagnazzo ◽  
Alessandro Deodati ◽  
Giuseppe Mastronuzzi
Keyword(s):  
Open Source ◽  
Structure From Motion ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Mapping Accuracy ◽  
Rapid Mapping ◽  
Source Structure

scholarly journals Evaluation of a low-cost approach to 2-D digital image correlation vs. a commercial stereo-DIC system in Brazilian testing of soil specimens

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
M. Arza-García ◽  
C. Núñez-Temes ◽  
J. A. Lorenzana ◽  
J. Ortiz-Sanz ◽  
A. Castro ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Field Measurements ◽  
Image Correlation ◽  
Strain Gauges ◽  
Source Image ◽  
Full Field ◽  
Cost Approach

AbstractDue to their cost, high-end commercial 3D-DIC (digital image correlation) systems are still inaccessible for many laboratories or small factories interested in lab testing materials. These professional systems can provide reliable and rapid full-field measurements that are essential in some laboratory tests with high-strain rate events or high dynamic loading. However, in many stress-controlled experiments, such as the Brazilian tensile strength (BTS) test of compacted soils, samples are usually large and fail within a timeframe of several minutes. In those cases, alternative low-cost methods could be successfully used instead of commercial systems. This paper proposes a methodology to apply 2D-DIC techniques using consumer-grade cameras and the open-source image processing software DICe (Sandia National Lab) for monitoring the standardized BTS test. Unlike most previous studies that theoretically estimate systematic errors or use local measures from strain gauges for accuracy assessment, we propose a contrast methodology with independent full-field measures. The displacement fields obtained with the low-cost system are benchmarked with the professional stereo-DIC system Aramis-3D (GOM GmbH) in four BTS experiments using compacted soil specimens. Both approaches proved to be valid tools for obtaining full-field measurements and showing the sequence of crack initiation, propagation and termination in the BTS, constituting reliable alternatives to traditional strain gauges. Mean deviations obtained between the low-cost 2D-DIC approach and Aramis-3D in measuring in-plane components were 0.08 mm in the perpendicular direction of loading (ΔX) and 0.06 mm in the loading direction (ΔY). The proposed low-cost approach implies considerable savings compared to commercial systems.

scholarly journals CAMERA CALIBRATION ACCURACY AT DIFFERENT UAV FLYING HEIGHTS

2017 ◽  
Vol XLII-2/W3 ◽  
pp. 595-600 ◽  
Author(s):  
A. R. Yusoff ◽  
M. F. M. Ariff ◽  
K. M. Idris ◽  
Z. Majid ◽  
A. K. Chong
Keyword(s):  
Camera Calibration ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Digital Camera ◽  
Bundle Adjustment ◽  
Digital Cameras ◽  
Mapping Accuracy ◽  
Image Mapping ◽  
Object Distance ◽  
Uav Image

Unmanned Aerial Vehicles (UAVs) can be used to acquire highly accurate data in deformation survey, whereby low-cost digital cameras are commonly used in the UAV mapping. Thus, camera calibration is considered important in obtaining high-accuracy UAV mapping using low-cost digital cameras. The main focus of this study was to calibrate the UAV camera at different camera distances and check the measurement accuracy. The scope of this study included camera calibration in the laboratory and on the field, and the UAV image mapping accuracy assessment used calibration parameters of different camera distances. The camera distances used for the image calibration acquisition and mapping accuracy assessment were 1.5&amp;thinsp;metres in the laboratory, and 15 and 25&amp;thinsp;metres on the field using a Sony NEX6 digital camera. A large calibration field and a portable calibration frame were used as the tools for the camera calibration and for checking the accuracy of the measurement at different camera distances. Bundle adjustment concept was applied in Australis software to perform the camera calibration and accuracy assessment. The results showed that the camera distance at 25&amp;thinsp;metres is the optimum object distance as this is the best accuracy obtained from the laboratory as well as outdoor mapping. In conclusion, the camera calibration at several camera distances should be applied to acquire better accuracy in mapping and the best camera parameter for the UAV image mapping should be selected for highly accurate mapping measurement.

scholarly journals THE USE OF THE UAV IMAGES FOR THE BUILDING 3D MODEL GENERATION

2018 ◽  
Vol XLII-4/W8 ◽  
pp. 217-223 ◽  
Author(s):  
G. Vacca ◽  
G. Furfaro ◽  
A. Dessì
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
3D Model ◽  
Low Cost ◽  
Laser Scanner ◽  
3D Models ◽  
Digital Cameras ◽  
Dense Matching ◽  
Uav Images ◽  
The University

<p><strong>Abstract.</strong> The growing interest in recent years in Unmanned Aerial Vehicles (UAVs) by the scientific community, software developers, and geomatics professionals, has led these systems to be used more and more widely, in different fields of engineering and architecture. This is thanks, above all, to their flexibility of use and low cost compared to traditional photogrammetric flights using expensive metric digital cameras or LiDAR sensors. In recent years, UAVs have also been used in the field of monitoring and inspection of public or private buildings that are remarkable in terms of size and architecture. This is mainly due to the focus a sustainability and resource efficiency in the building and infrastructure sector, which aims to extend their lifetimes. Through the use of remote checking using UAVs, the monitoring and inspection of buildings can be brought to a new level of quality and saving.</p><p> This paper focuses on the processing and study of 3D models obtained from images captured by an UAV. In particular, the authors wanted to study the accuracy gains achieved in the building 3D model obtained with both nadir and oblique UAV flights. The images from the flights were processed using Structure-for Motion-based approach for point cloud generation using dense image-matching algorithms implemented in an open source software. We used the open source software VisualSfM, developed by Chanchang Wu in collaboration with the University of Washington and Google. The dense matching plug-in integrated in its interface, PMVS/CMVS, made by Yasutaka Furukawa, was employed to generate the dense cloud. The achieved results were compare with those gained by Photoscan software by Agisoft and with 3D model from the Terrestrial Laser Scanner (TLS) survey.</p>

scholarly journals RealPi2dDIC: A Low-cost and open-source approach to in situ 2D Digital Image Correlation (DIC) applications

SoftwareX ◽  
2021 ◽  
Vol 13 ◽  
pp. 100645
Author(s):  
Partha Pratim Das ◽  
Muthu Ram Prabhu Elenchezhian ◽  
Vamsee Vadlamudi ◽  
Kenneth Reifsnider ◽  
Rassel Raihan
Keyword(s):  
Digital Image Correlation ◽  
Open Source ◽  
Digital Image ◽  
Low Cost ◽  
Image Correlation ◽  
2D Digital Image Correlation

scholarly journals DIGITAL IMAGE CORRELATION FROM COMMERCIAL TO FOS SOFTWARE: A MATURE TECHNIQUE FOR FULL-FIELD DISPLACEMENT MEASUREMENTS

2018 ◽  
Vol XLII-2 ◽  
pp. 91-95 ◽  
Author(s):  
V. Belloni ◽  
R. Ravanelli ◽  
A. Nascetti ◽  
M. Di Rita ◽  
D. Mattei ◽  
...  
Keyword(s):  
Digital Image Correlation ◽  
Open Source ◽  
Digital Image ◽  
Structural Engineering ◽  
Sample Surface ◽  
Image Correlation ◽  
Full Field ◽  
Field Displacement ◽  
University Of Rome ◽  
The University

In the last few decades, there has been a growing interest in studying non-contact methods for full-field displacement and strain measurement. Among such techniques, Digital Image Correlation (DIC) has received particular attention, thanks to its ability to provide these information by comparing digital images of a sample surface before and after deformation. The method is now commonly adopted in the field of civil, mechanical and aerospace engineering and different companies and some research groups implemented 2D and 3D DIC software. In this work a review on DIC software status is given at first. Moreover, a free and open source 2D DIC software is presented, named py2DIC and developed in Python at the Geodesy and Geomatics Division of DICEA of the University of Rome “La Sapienza”; its potentialities were evaluated by processing the images captured during tensile tests performed in the Structural Engineering Lab of the University of Rome “La Sapienza” and comparing them to those obtained using the commercial software Vic-2D developed by Correlated Solutions Inc, USA. The agreement of these results at one hundredth of millimetre level demonstrate the possibility to use this open source software as a valuable 2D DIC tool to measure full-field displacements on the investigated sample surface.

A simple methodology for recording petroglyphs using low-cost digital image correlation photogrammetry and consumer-grade digital cameras

2010 ◽  
Vol 37 (12) ◽  
pp. 3158-3169 ◽  
Author(s):  
Juan Ortiz Sanz ◽  
Maria de la Luz Gil Docampo ◽  
Santiago Martínez Rodríguez ◽  
María Teresa Rego Sanmartín ◽  
Gonzalo Meijide Cameselle
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Low Cost ◽  
Image Correlation ◽  
Digital Cameras

scholarly journals Digital Model in Close-Range Photogrammetry Using a Smartphone Camera

2021 ◽  
Vol 318 ◽  
pp. 04005
Author(s):  
Tariq N. Ataiwe ◽  
Israa Hatem ◽  
Hisham M. J. Al Sharaa
Keyword(s):  
Camera Calibration ◽  
3D Model ◽  
Accuracy Assessment ◽  
Low Cost ◽  
Calibration Model ◽  
Digital Cameras ◽  
Close Range Photogrammetry ◽  
Close Range ◽  
Chessboard Pattern ◽  
Image Orientation

Smartphones recently expanded the potential for low-cost close-range photogrammetry for 3D modeling. They enable the simultaneous collection of large amounts of data for a variety of requirements. It is possible to calculate image orientation elements and triangular coordinates in phases as in Relative and Absolute image orientation. This study demonstrates the photogrammetric 3D reconstruction approach that performs on tablets and smartphones as well. Images are taken with smartphone cameras of iPhone 6 and then calibrated automatically using normal calibration model for photogrammetry and computer vision on a PC, depend on Agisoft Lens add-on that imbedded in Agisoft program, and MATLAB camera calibration Toolbox, and by using an oriented bunch of images of chessboard pattern for large point cloud-based picture using matching. The camera calibration results indicate that the calibration processing routines pass without any error, and the accuracy of estimated IOPs was convenient compared with non-metric digital cameras and are more accurate in Agisoft Lens in terms of standard error. For the 3D model, 435 cameras were used, 428 cameras located from 435 are aligned in two photogrammetric software, Agisoft PhotoScan, and LPS. The number of tie points that are used in LPS is 10 tie points, and 4 control points which used to estimate the EOPs, and the number of tie points that are regenerated in Agisoft PhotoScan were 135.605 points, the number of Dense cloud 3,716,912 points are generated, for 3D model a number of 316,253 faces are generated, after processing the tiled model generated (6 levels, 1.25 cm/pix), the generated DEM having (2136×1774/pix), the dimensions of the generated high-resolution orthomosaic are (5520×4494, 4.47 cm/pix). For accuracy assessment, the Xerr. = 0.292 m, Yerr. = 0.38577 m, Zerr.= 0.2889 m, and the total RMS = 0.563 m in the estimated locations of the exterior orientation parameters.

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