Excitation-invariant pre-processing of thermographic data

2018 ◽  
Vol 232 (4) ◽  
pp. 435-446
Author(s):  
Serafeim Moustakidis ◽  
Athanasios Anagnostis ◽  
Apostolos Chondronasios ◽  
Patrik Karlsson ◽  
Kostas Hrissagis
Keyword(s):  
Composite Structures ◽  
Signal To Noise Ratio ◽  
Signal Reconstruction ◽  
Test Material ◽  
Test Surface ◽  
Nondestructive Testing Method ◽  
Uneven Heating ◽  
Processing Techniques ◽  
Inspection Techniques ◽  
Non Destructive

There is a large number of industries that make extensive use of composite materials in their respective sectors. This rise in composites’ use has necessitated the development of new non-destructive inspection techniques that focus on manufacturing quality assurance, as well as in-service damage testing. Active infrared thermography is now a popular nondestructive testing method for detecting defects in composite structures. Non-uniform emissivity, uneven heating of the test surface, and variation in thermal properties of the test material are some of the crucial factors in experimental thermography. These unwanted thermal effects are typically coped with the application of a number of well-established thermographic techniques including pulse phase thermography and thermographic signal reconstruction. This article addresses this problem of the induced uneven heating at the pre-processing phase prior to the application of the thermographic processing techniques. To accomplish this, a number of excitation invariant pre-processing techniques were developed and tested in this article addressing the unwanted effect of non-uniform excitation in the collected thermographic data. Various fitting approaches were validated in light of modeling the non-uniform heating effect, and new normalization approaches were proposed following a time-dependent framework. The proposed pre-processing techniques were validated on a testing composite sample with pre-determined defects. The results demonstrated the effectiveness of the proposed processing algorithms in terms of removing the unwanted heat distribution effect along with the signal-to-noise ratio of the produced infrared images.

scholarly journals Comparison of Cooled and Uncooled IR Sensors by Means of Signal-to-Noise Ratio for NDT Diagnostics of Aerospace Grade Composites

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3381 ◽  
Author(s):  
Shakeb Deane ◽  
Nicolas P. Avdelidis ◽  
Clemente Ibarra-Castanedo ◽  
Hai Zhang ◽  
Hamed Yazdani Nezhad ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Non Destructive Testing ◽  
Signal To Noise ◽  
Destructive Testing ◽  
Ir Camera ◽  
Thermal Cameras ◽  
Aerial Vehicle ◽  
Noise Ratio ◽  
Processing Techniques ◽  
Non Destructive

This work aims to address the effectiveness and challenges of non-destructive testing (NDT) by active infrared thermography (IRT) for the inspection of aerospace-grade composite samples and seeks to compare uncooled and cooled thermal cameras using the signal-to-noise ratio (SNR) as a performance parameter. It focuses on locating impact damages and optimising the results using several signal processing techniques. The work successfully compares both types of cameras using seven different SNR definitions, to understand if a lower-resolution uncooled IR camera can achieve an acceptable NDT standard. Due to most uncooled cameras being small, lightweight, and cheap, they are more accessible to use on an unmanned aerial vehicle (UAV). The concept of using a UAV for NDT on a composite wing is explored, and the UAV is also tracked using a localisation system to observe the exact movement in millimetres and how it affects the thermal data. It was observed that an NDT UAV can access difficult areas and, therefore, can be suggested for significant reduction of time and cost.

Enhanced image processing for infrared non-destructive testing

2014 ◽  
Vol 22 (4) ◽  
Author(s):  
F. Lopez ◽  
X. Maldague ◽  
C. Ibarra-Castanedo
Keyword(s):  
Signal To Noise Ratio ◽  
Signal Reconstruction ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Multivariate Statistical ◽  
Depth Analysis ◽  
Thermal Data ◽  
Signal Contrast ◽  
Pulsed Phase Thermography ◽  
Non Destructive

AbstractThis paper presents a review and in-depth analysis of three of the most popular techniques for processing PT images: differential absolute contrast, thermographic signal reconstruction and pulsed phase thermography. The fundamental concepts of the three techniques are reviewed and their application on thermal data obtained from the PT inspection on a carbon fibre reinforced specimen is analysed. Furthermore, a new promissory technique based on multivariate statistical analysis is also introduced and evaluated. The performance of the techniques is evaluated in terms of the signal-to-noise ratio at maximum signal contrast.

Non-Destructive Testing of Thermoplastic Carbon Composite Structures

2020 ◽  
Vol 2020 (1) ◽  
pp. 34-52
Author(s):  
Rafał Szymański
Keyword(s):  
Composite Structures ◽  
Ultrasonic Method ◽  
Composite Panel ◽  
Aviation Industry ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulse Technique ◽  
Thermoplastic Matrix ◽  
The Subject ◽  
Non Destructive

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.

scholarly journals Quaternion Processing Techniques for Color Synthesized NDT Thermography

2021 ◽  
Vol 11 (2) ◽  
pp. 790
Author(s):  
Pablo Venegas ◽  
Rubén Usamentiaga ◽  
Juan Perán ◽  
Idurre Sáez de Ocáriz
Keyword(s):  
Signal To Noise Ratio ◽  
High Capacity ◽  
Synthetic Data ◽  
Relevant Information ◽  
Color Images ◽  
Destructive Testing ◽  
Application Procedure ◽  
Definition Of ◽  
Characterization Procedure ◽  
Processing Techniques

Infrared thermography is a widely used technology that has been successfully applied to many and varied applications. These applications include the use as a non-destructive testing tool to assess the integrity state of materials. The current level of development of this application is high and its effectiveness is widely verified. There are application protocols and methodologies that have demonstrated a high capacity to extract relevant information from the captured thermal signals and guarantee the detection of anomalies in the inspected materials. However, there is still room for improvement in certain aspects, such as the increase of the detection capacity and the definition of a detailed characterization procedure of indications, that must be investigated further to reduce uncertainties and optimize this technology. In this work, an innovative thermographic data analysis methodology is proposed that extracts a greater amount of information from the recorded sequences by applying advanced processing techniques to the results. The extracted information is synthesized into three channels that may be represented through real color images and processed by quaternion algebra techniques to improve the detection level and facilitate the classification of defects. To validate the proposed methodology, synthetic data and actual experimental sequences have been analyzed. Seven different definitions of signal-to-noise ratio (SNR) have been used to assess the increment in the detection capacity, and a generalized application procedure has been proposed to extend their use to color images. The results verify the capacity of this methodology, showing significant increments in the SNR compared to conventional processing techniques in thermographic NDT.

scholarly journals Potential of spectroscopic analyses for non-destructive estimation of tea quality-related metabolites in fresh new leaves

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroto Yamashita ◽  
Rei Sonobe ◽  
Yuhei Hirono ◽  
Akio Morita ◽  
Takashi Ikka
Keyword(s):  
Short Wave ◽  
Machine Learning Algorithms ◽  
Estimation Methods ◽  
Chemical Information ◽  
Tea Quality ◽  
The Mean ◽  
Processing Techniques ◽  
Spectral Patterns ◽  
Physical And Chemical ◽  
Non Destructive

AbstractSpectroscopic sensing provides physical and chemical information in a non-destructive and rapid manner. To develop non-destructive estimation methods of tea quality-related metabolites in fresh leaves, we estimated the contents of free amino acids, catechins, and caffeine in fresh tea leaves using visible to short-wave infrared hyperspectral reflectance data and machine learning algorithms. We acquired these data from approximately 200 new leaves with various status and then constructed the regression model in the combination of six spectral patterns with pre-processing and five algorithms. In most phenotypes, the combination of de-trending pre-processing and Cubist algorithms was robustly selected as the best combination in each round over 100 repetitions that were evaluated based on the ratio of performance to deviation (RPD) values. The mean RPD values were ranged from 1.1 to 2.7 and most of them were above the acceptable or accurate threshold (RPD = 1.4 or 2.0, respectively). Data-based sensitivity analysis identified the important hyperspectral regions around 1500 and 2000 nm. Present spectroscopic approaches indicate that most tea quality-related metabolites can be estimated non-destructively, and pre-processing techniques help to improve its accuracy.

The effect of the indenter elasticity on the Hertzian fracture of brittle materials

1973 ◽  
Vol 334 (1596) ◽  
pp. 95-117 ◽  
Keyword(s):  
Fracture Stress ◽  
Opposite Effect ◽  
Test Material ◽  
Test Surface ◽  
Dynamic Tests ◽  
Frictional Forces ◽  
Consistent Increase ◽  
Static And Dynamic Tests ◽  
Ring Crack ◽  
Ring Cracks

A spherical indenter loaded statically or dynamically into contact with the surface of a brittle material produces a well-defined ring crack. This phenomenon, when interpreted by the Hertz theory of elastic contact, provides a convenient test for the strength of the material. If the elastic modulus of the indenter is different from that of the test material, e. g. a steel indenter in contact with a glass surface, frictional forces are brought into play at the interface which modify the Hertz distribution of contact stress. This effect has been examined both theo­retically and experimentally. An indenter which is more rigid than the test surface is shown to lead to an apparent increase in fracture strength of the material, a less rigid indenter has the opposite effect. Static and dynamic tests of plate glass showed a consistent increase in apparent fracture stress of about 50 % using spherical steel indenters compared with glass indenters. This increase agrees well with the influence of friction upon the Hertzian stress calculated theoretically. The average radius of the ring cracks produced by steel indenters was observed to be greater than that produced by glass indenters, an effect of friction also predicted by the theory. Secondary ring cracks of smaller radius have frequently been observed during unloading of a steel indenter. These were not found when a glass indenter was used and an explanation is suggested in terms of the frictional effect which arises from a difference in elasticity between the indenter and the test surface.

Assessing the Condition and Estimating the Remaining Lives of Pressure Components in a Methanol Plant Reformer: Part 1 — NDE

2016 ◽  
Author(s):  
Brian E. Shannon ◽  
Carl E. Jaske ◽  
Gustavo Miranda
Keyword(s):  
High Temperature ◽  
Creep Damage ◽  
Sensor Technology ◽  
Special Focus ◽  
Laser Measurements ◽  
Typical Data ◽  
Multiple Sensor ◽  
High Temperature Components ◽  
Inspection Techniques ◽  
Non Destructive

Statoil Tjelbergodden operates a 2,400 ton/day methanol plant in Norway. In order to assess the condition and reliability of high temperature components within the reformer, a series of advanced non-destructive examination (NDE) technologies were applied to radiant catalyst tubes, outlet pigtails, and outlet collection headers. The inspection techniques were selected and developed to provide data that could easily be used in the engineering assessment of the high-temperature components. Special focus was given to detecting and quantifying high-temperature creep damage. This paper describes the NDE techniques that were employed and provides examples of typical data obtained by using the techniques. Catalyst tubes were inspected using the H SCAN® (Figure 1) multiple sensor technology. This technique utilizes two types of ultrasonic sensors, eddy current sensors, laser measurements, and elevation location sensors in scanning each catalyst tube. The H SCAN® P-CAT™ (Figure 2) technique is applied to outlet pigtails, while the H SCAN® H-CAT™ (Figure 3) technique is applied to outlet headers.

Review on Non-Destructive Testing Technique of Eddy Current Pulsed Thermography

2015 ◽  
Vol 742 ◽  
pp. 128-131 ◽  
Author(s):  
Jian Min Zhou ◽  
Jun Yang ◽  
Qi Wan
Keyword(s):  
Eddy Current ◽  
Signal Reconstruction ◽  
Infrared Image ◽  
Principal Component ◽  
Research Progress ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulsed Thermography ◽  
Pulsed Phase Thermography ◽  
Non Destructive

This paper introduces the theory of eddy current pulsed thermography and expounds the research status of eddy current pulsed thermography in application and information extraction. Thermographic signal reconstruction, pulsed phase thermography, principal component analysis were introuduced in this paper and listed some fusion multiple methods to acquire information from infrared image. At last, it summarizes research progress, existing problem and deelopment of eddy current pulsed thermography.

A Review of Ultrasonic Application on Non-destructive Testing Method for Concrete Structure

2014 ◽  
Vol 70 (3) ◽  
Author(s):  
Nasarudin Ahmad ◽  
Ruzairi Abdul Rahim ◽  
Herlina Abdul Rahim ◽  
Mohd Hafiz Fazlul Rahiman
Keyword(s):  
Concrete Structure ◽  
High Speed ◽  
Structural Integrity ◽  
Surface Hardness ◽  
Concrete Surface ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Surface Absorption ◽  
Processing Techniques ◽  
Non Destructive

Although the technique of using ultrasound has reached maturity by given the extent of the development of sensors, but the use of the various areas still can be explore. Many types of ultrasonic sensors are still at conventional in use especially for measurement equipment in the industry. With the advancement of signal processing techniques, high-speed computing, and the latest techniques in image formation based Non-destructive testing (NDT) methods, the usage of ultrasound in concrete NDT testing is very extensive because the technique is very simple and should not damage the concrete structure to be investigated. Many of the parameters need to be tested using ultrasound techniques to concrete can be realized. Starting with the initial process for of concrete mixing until the concrete matured to the age of century old. Various tests are available to test a variety of non-destructive of concrete completely, in which there is no damage to the concrete, through those where the concrete surface is damaged a bit, to partially destructive testing, such as core tests and insertion and pull-off test, which surface to be repaired after the test. Testing parameter features that can be evaluated using non-destructive testing and destructive testing of some rather large and include basic parameters such as density, elastic modulus and strength and surface hardness and surface absorption, and reinforcement location, size and distance from the surface. In some cases it is also possible to check the quality of the workmanship and structural integrity of the ability to detect voids, cracks and delamination. A review of NDT using ultrasound on concrete are presented in this paper to highlight the important aspect to consider when one to consider the application and development of ultrasound testing on concrete by considering ultrasound signal capturing, processing and presenting.

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