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.

Suppression of high‐energy noise using an alternative stacking procedure

Geophysics ◽  
1989 ◽  
Vol 54 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Jakob B. U. Haldorsen ◽  
Paul A. Farmer
Keyword(s):  
Seismic Data ◽  
Traditional Approach ◽  
Signal To Noise Ratio ◽  
Synthetic Data ◽  
High Amplitude ◽  
High Energy ◽  
Data Set ◽  
Trimmed Mean ◽  
Fold Reduction ◽  
Processing Techniques

Occasionally, seismic data contain transient noise that can range from being a nuisance to becoming intolerable when several seismic vessels try simultaneously to collect data in an area. The traditional approach to solving this problem has been to allocate time slots to the different acquisition crews; the procedure, although effective, is very expensive. In this paper a statistical method called “trimmed mean stack” is evaluated as a tool for reducing the detrimental effects of noise from interfering seismic crews. Synthetic data, as well as field data, are used to illustrate the efficacy of the technique. Although a conventional stack gives a marginally better signal‐to‐noise ratio (S/N) for data without interference noise, typical usage of the trimmed mean stack gives a reduced S/N equivalent to a fold reduction of about 1 or 2 percent. On the other hand, for a data set containing high‐energy transient noise, trimming produces stacked sections without visible high‐amplitude contaminating energy. Equivalent sections produced with conventional processing techniques would be totally unacceptable. The application of a trimming procedure could mean a significant reduction in the costs of data acquisition by allowing several seismic crews to work simultaneously.

Use of BIM in rehabilitation and assessment of the built heritage: from the visible to the intangible

2019 ◽  
Author(s):  
Hélder S. Sousa ◽  
Carmen Sguazzo ◽  
Manuel Cabaleiro
Keyword(s):  
Relevant Information ◽  
Destructive Testing ◽  
Building Information Modelling ◽  
Information Modelling ◽  
Traditional Assessment ◽  
Existing Structures ◽  
Built Heritage ◽  
Building Information ◽  
New Construction ◽  
Definition Of

<p>Building Information Modelling (BIM) has been increasingly expanding its application to different fields of civil engineering and Historic building information modelling (HBIM) is an example of that. Although, the concept has already drawn the attention of several researchers, there are still many limitations to a full and holistic process that may take HBIM to the same level of applicability that BIM used for new construction has.</p><p>Traditionally, assessment of existing structures, specially heritage structures, begin with the documentation of all important information dealing with the history, characteristics, type, material, uses and applied techniques, among other relevant information that may be retrieved by different sources. Further on, a geometrical survey accompanied with visual inspection and non or semi destructive testing leads to the geometry definition of the structure and to its condition (damage/defects) mapping. All of this information, must be analysed for consequent structural assessment and after stored in a proper database in order to monitor the condition change of the structure along time.</p><p>This paper, presents a framework for use of BIM in rehabilitation and assessment of the built heritage, based on the review of recent works, as to allow a better understanding of the potential for the management of important and significant structures. The paper deals with the dilemma of bringing what a “traditional” assessment can see to how intangible information may be applied.</p>

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.

scholarly journals Sustainability and Stakeholder Awareness: A Case Study of a Scottish University

2021 ◽  
Vol 13 (8) ◽  
pp. 4186
Author(s):  
Abdulhakeem Raji ◽  
Abeer Hassan
Keyword(s):  
Signaling Theory ◽  
Relevant Information ◽  
Voluntary Exercise ◽  
Communication Tool ◽  
Individual Interviews ◽  
Study Approach ◽  
Research Findings ◽  
Definition Of ◽  
The University

This paper adopted a case study approach to investigate the sustainability practices of a Scottish university in order to understand if sustainability forms part of its central policy agenda. As such, the paper focuses on the levels of awareness and disclosure of their sustainable practices, measuring the impacts and effectiveness of those initiatives. This paper introduces signaling theory to explore the idea that appropriate communication via integrated thinking can close the gap between the organization and its stakeholders. We believe that the provision of this relevant information will lead to better communication between the organization and its stakeholders, supporting a signaling theory interpretation. Therefore, we are suggesting that integrated thinking is an internal process that organizations can follow to increase the level of disclosure as a communication tool with stakeholders. From the literature reviewed, four themes were identified (definition of university sustainability, sustainability awareness, disclosure framework within universities, and level of accountability). The research adopted a pragmatic view and conducted individual interviews with participants belonging to three stakeholder groups (members of the university’s senior management, the governing council, and the student union executive). Although this study focused on just one Scottish university, it should still provide some insight for the better understanding of the underpinning issues surrounding the sustainability accountability practices of Scottish universities in general. The research findings indicated that the university prioritized only two sustainability dimensions—economic and environmental—and that the university still perceived sustainability as a voluntary exercise. Additionally, it is evident that the university had no framework in place for measuring its sustainability delivery—and therefore had no established medium of communicating these activities to its stakeholders. Moreover, research findings showed that the social and educational context of sustainability was lacking at the university. The university has done little or nothing to educate its stakeholders on sustainability.

scholarly journals Stochastic resonance in periodically driven bistable systems subjected to anomalous diffusion

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
F. Naha Nzoupe ◽  
Alain M. Dikandé
Keyword(s):  
Stochastic Resonance ◽  
Signal To Noise Ratio ◽  
Planck Equation ◽  
Relevant Information ◽  
Periodic Signal ◽  
Signal To Noise ◽  
Periodically Driven ◽  
Loop Area ◽  
Bistable Systems ◽  
Noise Ratio

AbstractThe occurrence of stochastic resonance in bistable systems undergoing anomalous diffusions, which arise from density-dependent fluctuations, is investigated with an emphasis on the analytical formulation of the problem as well as a possible analytical derivation of key quantifiers of stochastic resonance. The nonlinear Fokker–Planck equation describing the system dynamics, together with the corresponding Ito–Langevin equation, is formulated. In the linear response regime, analytical expressions of the spectral amplification, of the signal-to-noise ratio and of the hysteresis loop area are derived as quantifiers of stochastic resonance. These quantifiers are found to be strongly dependent on the parameters controlling the type of diffusion; in particular, the peak characterizing the signal-to-noise ratio occurs only in close ranges of parameters. Results introduce the relevant information that, taking into consideration the interactions of anomalous diffusive systems with a periodic signal, can provide a better understanding of the physics of stochastic resonance in bistable systems driven by periodic forces.

scholarly journals Identification and inclusion of gender factors in retrospective cohort studies: the GOING-FWD framework

2021 ◽  
Vol 6 (4) ◽  
pp. e005413
Author(s):  
Valeria Raparelli ◽  
Colleen M. Norris ◽  
Uri Bender ◽  
Maria Trinidad Herrero ◽  
Alexandra Kautzky-Willer ◽  
...  
Keyword(s):  
Outcome Measurement ◽  
Meta Analysis ◽  
Synthetic Data ◽  
Well Being ◽  
Pooled Analysis ◽  
Research Network ◽  
Local Analysis ◽  
Related Factors ◽  
Measurement Framework ◽  
Definition Of

Gender refers to the socially constructed roles, behaviours, expressions and identities of girls, women, boys, men and gender diverse people. Gender-related factors are seldom assessed as determinants of health outcomes, despite their powerful contribution. The Gender Outcomes INternational Group: to Further Well-being Development (GOING-FWD) project developed a standard five-step methodology applicable to retrospectively identify gender-related factors and assess their relationship to outcomes across selected cohorts of non-communicable chronic diseases from Austria, Canada, Spain, Sweden. Step 1 (identification of gender-related variables): Based on the gender framework of the Women Health Research Network (ie, identity, role, relations and institutionalised gender), and available literature for a certain disease, an optimal ‘wish-list’ of gender-related variables was created and discussed by experts. Step 2 (definition of outcomes): Data dictionaries were screened for clinical and patient-relevant outcomes, using the International Consortium for Health Outcome Measurement framework. Step 3 (building of feasible final list): a cross-validation between variables per database and the ‘wish-list’ was performed. Step 4 (retrospective data harmonisation): The harmonisation potential of variables was evaluated. Step 5 (definition of data structure and analysis): The following analytic strategies were identified: (1) local analysis of data not transferable followed by a meta-analysis combining study-level estimates; (2) centrally performed federated analysis of data, with the individual-level participant data remaining on local servers; (3) synthesising the data locally and performing a pooled analysis on the synthetic data and (4) central analysis of pooled transferable data. The application of the GOING-FWD multistep approach can help guide investigators to analyse gender and its impact on outcomes in previously collected data.

scholarly journals Velody 2—Resilient High-Capacity MIDI Steganography for Organ and Harpsichord Music

2020 ◽  
Vol 11 (1) ◽  
pp. 39
Author(s):  
Eric Järpe ◽  
Mattias Weckstén
Keyword(s):  
Mean Absolute Error ◽  
Signal To Noise Ratio ◽  
High Capacity ◽  
Absolute Error ◽  
Music Technology ◽  
Alternative Methods ◽  
File Size ◽  
User Friendly ◽  
Different Levels ◽  
Better Than

A new method for musical steganography for the MIDI format is presented. The MIDI standard is a user-friendly music technology protocol that is frequently deployed by composers of different levels of ambition. There is to the author’s knowledge no fully implemented and rigorously specified, publicly available method for MIDI steganography. The goal of this study, however, is to investigate how a novel MIDI steganography algorithm can be implemented by manipulation of the velocity attribute subject to restrictions of capacity and security. Many of today’s MIDI steganography methods—less rigorously described in the literature—fail to be resilient to steganalysis. Traces (such as artefacts in the MIDI code which would not occur by the mere generation of MIDI music: MIDI file size inflation, radical changes in mean absolute error or peak signal-to-noise ratio of certain kinds of MIDI events or even audible effects in the stego MIDI file) that could catch the eye of a scrutinizing steganalyst are side-effects of many current methods described in the literature. This steganalysis resilience is an imperative property of the steganography method. However, by restricting the carrier MIDI files to classical organ and harpsichord pieces, the problem of velocities following the mood of the music can be avoided. The proposed method, called Velody 2, is found to be on par with or better than the cutting edge alternative methods regarding capacity and inflation while still possessing a better resilience against steganalysis. An audibility test was conducted to check that there are no signs of audible traces in the stego MIDI files.

scholarly journals Lightweight and Efficient Image Dehazing Network Guided by Transmission Estimation from Real-World Hazy Scenes

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 960
Author(s):  
Zhan Li ◽  
Jianhang Zhang ◽  
Ruibin Zhong ◽  
Bir Bhanu ◽  
Yuling Chen ◽  
...  
Keyword(s):  
Real World ◽  
Evaluation Criteria ◽  
Synthetic Data ◽  
Network Size ◽  
Image Dehazing ◽  
Depth Data ◽  
Network Training ◽  
Dark Channel ◽  
Processing Techniques ◽  
Transmission Estimation

In this paper, a transmission-guided lightweight neural network called TGL-Net is proposed for efficient image dehazing. Unlike most current dehazing methods that produce simulated transmission maps from depth data and haze-free images, in the proposed work, guided transmission maps are computed automatically using a filter-refined dark-channel-prior (F-DCP) method from real-world hazy images as a regularizer, which facilitates network training not only on synthetic data, but also on natural images. A double-error loss function that combines the errors of a transmission map with the errors of a dehazed image is used to guide network training. The method provides a feasible solution for introducing priors obtained from traditional non-learning-based image processing techniques as a guide for training deep neural networks. Extensive experimental results demonstrate that, in terms of several reference and non-reference evaluation criteria for real-world images, the proposed method can achieve state-of-the-art performance with a much smaller network size and with significant improvements in efficiency resulting from the training guidance.

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.

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