Studies on Digital Shearography for Testing of Aircraft Composite Structures and Honeycomb-Based Specimen

2011 ◽  
Vol 121-126 ◽  
pp. 1264-1268 ◽  
Author(s):  
Hui Juan Feng ◽  
Jian Zhang ◽  
Xiang Kai Liu
Keyword(s):  
Composite Structures ◽  
Vibration Isolation ◽  
Surface Deformation ◽  
Processing Technique ◽  
Inspection System ◽  
Measuring Device ◽  
Imaging Processing ◽  
Full Field ◽  
Full Field Measurement ◽  
Digital Imaging Processing

This paper reviews shearography and its applications for testing of aircraft composite structures and honeycomb-based specimen. Shearography is a laser-based interferometry in conjunction with the digital imaging processing technique for full-field measurement of surface deformation. It reveals defects in an object by looking for defect-induced deformation anomalies. It does not require special vibration isolation, and with the development of a small and mobile measuring device (portable inspection system), it can be employed easily in field/factory environments.

scholarly journals Non Destructive Investigation of Defects in Composite Structures by Full-Field Measurement Methods

2013 ◽  
Vol 550 ◽  
pp. 135-142
Author(s):  
Elodie Péronnet ◽  
Marie Laetitia Pastor ◽  
Richard Huillery ◽  
Olivier Dalverny ◽  
Sébastien Mistou ◽  
...  
Keyword(s):  
Defect Detection ◽  
Field Measurement ◽  
Composite Structures ◽  
Measurement Methods ◽  
Sandwich Composite ◽  
Full Field ◽  
X Ray ◽  
Full Field Measurement ◽  
Application Fields ◽  
Non Destructive

This paper presents different interests of non destructive full-field measurement. More precisely, it focuses on the characterization and the comparison of the X-ray tomography and two methods of infrared thermography in order to define the defect detection limits and to precise the specific application fields for each technique on multi-layered and sandwich composite structures. The obtained results are qualitatively and quantitatively analyzed.

scholarly journals Foreground Scattering Elimination by Inverse Lock-in-Like Spatial Modulation

Vision ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 37
Author(s):  
Yueyu Lin ◽  
Sune Svanberg
Keyword(s):  
Gaussian Mixture Models ◽  
Main Idea ◽  
Gaussian Mixture ◽  
Processing Technique ◽  
Spatial Modulation ◽  
Imaging Processing ◽  
Close Range ◽  
Static Feature ◽  
Lock In ◽  
Digital Imaging Processing

We describe a simple approach to enhance vision, which is impaired by close range obscuring and/or scattering structures. Such structures may be found on a dirty windscreen of a car, or by tree branches blocking the vision of objects behind. The main idea is to spatially modulate the obscuration, either by periodically moving the detector/eye or by letting the obscuration modulate itself, such as branches swinging in the wind. The approach has similarities to electronic lock-in techniques, where the feature of interest is modulated to enable it to be isolated from the strong perturbing background, but now, we modulate the background instead to isolate the static feature of interest. Thus, the approach can be denoted as “inverse lock-in-like spatial modulation”. We also apply a new digital imaging processing technique based on a combination of the Interframe Difference and Gaussian Mixture models for digital separation between the objects of interest and the background, and make connections to the Gestalt vision psychology field.

scholarly journals Raman and Infrared Thermometry for Microsystems

2013 ◽  
Vol 5 (3) ◽  
Author(s):  
Leslie M. Phinney ◽  
Wei-Yang Lu ◽  
Justin R. Serrano
Keyword(s):  
Data Collection ◽  
Spatial Resolution ◽  
Infrared Imaging ◽  
Silicon On Insulator ◽  
Pixel Size ◽  
Full Field ◽  
Infrared Thermometry ◽  
Full Field Measurement ◽  
Typical Data ◽  
Field Temperature

This paper reports and compares Raman and infrared thermometry measurements along the legs and on the shuttle of a SOI (silicon on insulator) bent-beam thermal microactuator. Raman thermometry offers micron spatial resolution and measurement uncertainties of ±10 K. Typical data collection times are a minute per location leading to measurement times on the order of hours for a complete temperature profile. Infrared thermometry obtains a full-field measurement so the data collection time is on the order of a minute. The spatial resolution is determined by the pixel size, 25 μm by 25 μm for the system used, and infrared thermometry also has uncertainties of ±10 K after calibration with a nonpackaged sample. The Raman and infrared measured temperatures agreed both qualitatively and quantitatively. For example, when the thermal microactuator was operated at 7 V, the peak temperature on an interior leg is 437 K ± 10 K and 433 K ± 10 K from Raman and infrared thermometry, respectively. The two techniques are complementary for microsystems characterization when infrared imaging obtains a full-field temperature measurement and Raman thermometry interrogates regions for which higher spatial resolution is required.

Imaging processing technique to measure plant infection severity

2006 ◽  
Author(s):  
Shengpan Zhu ◽  
Huirong Xu ◽  
Yibin Ying ◽  
Huanyu Jiang
Keyword(s):  
Processing Technique ◽  
Imaging Processing ◽  
Plant Infection

scholarly journals A Review of Surface Deformation and Strain Measurement Using Two-Dimensional Digital Image Correlation

2016 ◽  
Vol 23 (3) ◽  
pp. 461-480 ◽  
Author(s):  
Sze-Wei Khoo ◽  
Saravanan Karuppanan ◽  
Ching-Seong Tan
Keyword(s):  
Digital Image Correlation ◽  
Digital Image ◽  
Strain Measurement ◽  
Surface Deformation ◽  
Optical Measurement ◽  
Image Correlation ◽  
Two Dimensional ◽  
Full Field ◽  
Computation Efficiency ◽  
Dimensional Measurements

Abstract Among the full-field optical measurement methods, the Digital Image Correlation (DIC) is one of the techniques which has been given particular attention. Technically, the DIC technique refers to a non-contact strain measurement method that mathematically compares the grey intensity changes of the images captured at two different states: before and after deformation. The measurement can be performed by numerically calculating the displacement of speckles which are deposited on the top of object’s surface. In this paper, the Two-Dimensional Digital Image Correlation (2D-DIC) is presented and its fundamental concepts are discussed. Next, the development of the 2D-DIC algorithms in the past 33 years is reviewed systematically. The improvement of 2DDIC algorithms is presented with respect to two distinct aspects: their computation efficiency and measurement accuracy. Furthermore, analysis of the 2D-DIC accuracy is included, followed by a review of the DIC applications for two-dimensional measurements.

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