scholarly journals An Infrared Defect Sizing Method Based on Enhanced Phase Images

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3626 ◽  
Author(s):  
Yanjie Wei ◽  
Zhilong Su ◽  
Shuangshuang Mao ◽  
Dongsheng Zhang
Keyword(s):  
Infrared Thermography ◽  
Inspection System ◽  
Effective Diameter ◽  
Processing Scheme ◽  
Low Contrast ◽  
Full Field ◽  
Engineering Society ◽  
Glass Fiber Reinforced ◽  
Fourier Phase Analysis ◽  
Phase Images

Infrared thermography (IRT) is a full-field, contactless technique that has been widely used for nondestructive evaluation of structural materials due to many advantages. One of the major limitations of IRT is the fuzzy edge and low contrast in the inspected images—as well as the cost of the system. An efficient image post-processing with an affordable and portable device is of great interest to the engineering society. In this study, a convenient and economical inspection system using common halogen lamps was constructed. The corresponding image-processing scheme, which includes Fourier phase analysis and specific image enhancement was developed to identify defects with sharp and clear edges and good contrast. This system was applied to localized of defects in glass-fiber-reinforced composite panels. The results showed that defects with an effective diameter as small as 5 mm can be detected with excellent image quality. As a conclusion, the developed system provides an economic alternative to traditional infrared thermography which is able to identify defects with good qualities.

Theoretical and Experimental Study on Nondestructive Pulse Phase Infrared Thermography Testing Technology

2011 ◽  
Vol 314-316 ◽  
pp. 1483-1486
Author(s):  
Qing Ju Tang ◽  
Jun Yan Liu ◽  
Yang Wang
Keyword(s):  
Experimental Study ◽  
Infrared Thermography ◽  
Testing Effect ◽  
Experimental Results ◽  
Composite Specimen ◽  
Experimental Platform ◽  
Phase Images ◽  
Testing Technology ◽  
Pulsed Phase Thermography ◽  
Non Destructive

The non-destructive pulsed phase thermography technique was used to detect metal specimen with flat blind-bottom holes and composite specimen with sticky areas. An experimental platform was built base on the analysis of the pulsed phase thermography testing principle. Experimental results show the different testing effect of the original thermography, amplitude and phase images.

Application of the Ultrasound-Infrared Thermography Technique for Non-Destructive Evaluation of Defects in Shoe Bonding Parts

2010 ◽  
Vol 123-125 ◽  
pp. 823-826 ◽  
Author(s):  
Seung Hyun Choi ◽  
Lee Ku Kwac ◽  
Jae Yeol Kim
Keyword(s):  
Infrared Thermography ◽  
Evaluation Method ◽  
Local Heat ◽  
Inspection System ◽  
System Configuration ◽  
Thermal Camera ◽  
Ultrasound Waves ◽  
Wide Range ◽  
Defective Surface ◽  
Non Destructive

The infrared thermography technique is being applied in many areas. Particularly these days, non-destructive inspection and evaluation using the ultrasound-infrared thermography technique are hogging the spotlight in a wide range of study areas. The ultrasound-infrared thermography technique uses the principle that ultrasound waves projected to objects with cracks or defects at connections generate local heat from the defective surface. In this research, introduce nondestructive evaluation method for total inspection of special shoes applying Ultrasound Infrared thermography Technique. Performance of the proposed method are shown by through thermo-Image. The total inspection system using infrared thermal camera for special shoes, its applicability, and system configuration are introduced.

scholarly journals The locus of flicker adaptation in the migraine visual system: A dichoptic study

Cephalalgia ◽  
2012 ◽  
Vol 33 (1) ◽  
pp. 5-19 ◽  
Author(s):  
Michel Thabet ◽  
Frances Wilkinson ◽  
Hugh R Wilson ◽  
Olivera Karanovic
Keyword(s):  
Visual System ◽  
Interocular Transfer ◽  
Neural Model ◽  
Inhibitory Neurons ◽  
High Contrast ◽  
Low Contrast ◽  
Full Field ◽  
Dichoptic Viewing ◽  
High Stimulus ◽  
And Control

Background Flickering light has been shown to sensitize the migraine visual system at high stimulus contrast while elevating thresholds at low contrast. The present study employs a dichoptic psychophysical paradigm to ask whether the abnormal adaptation to flicker in migraine occurs before or after the binocular combination of inputs from the two eyes in the visual cortex. Methods Following adaptation to high contrast flicker presented to one eye only, flicker contrast increment thresholds were measured in each eye separately using dichoptic viewing. Results Modest interocular transfer of adaptation was seen in both migraine and control groups at low contrast. Sensitization at high contrast in migraine relative to control participants was seen in the adapted eye only, and an unanticipated threshold elevation occurred in the non-adapted eye. Migraineurs also showed significantly lower aversion thresholds to full field flicker than control participants, but aversion scores and increment thresholds were not correlated. Conclusions The results are simulated with a three-stage neural model of adaptation that points to strong adaptation at monocular sites prior to binocular combination, and weaker adaptation at the level of cortical binocular neurons. The sensitization at high contrast in migraine is proposed to result from stronger adaptation of inhibitory neurons, which act as a monocular normalization pool.

Surface Defect Inspection and Classification of Segment Magnet by Using Machine Vision Technique

2011 ◽  
Vol 339 ◽  
pp. 32-35 ◽  
Author(s):  
Hong Hai Jiang ◽  
Guo Fu Yin
Keyword(s):  
Image Processing ◽  
Machine Vision ◽  
Surface Defects ◽  
Processing System ◽  
Support Vector ◽  
Inspection System ◽  
Low Contrast ◽  
Constituent Material ◽  
Canny Edge

In this paper, we propose a machine vision based approach for detecting and classifying irregular low-contrast surface defects of segment magnet. The constituent material of it is ferrite which varies from silver gray to black in color .For this reason, the defects embedded in a low-contrast surface show no big different from its surrounding region, and even worse, all the surfaces and chamfers of segment magnet must be inspected. Our system is able to analyze all surfaces under inspection, to discover and classify its defects by means of image processing algorithms and support vector machine (SVM). A working prototype of the system has been built and tested to validate the proposed approach and to reproduce the difficult issues of the inspection system. The developed prototype includes three subsystems: an array of several CCD area cameras (Fig.1); a controllable roller LED light source(Fig.1); and a PC-based image processing system. The detection of the defects is performed by means of Canny edge detection, morphology and other feature extraction operations. The image processing and classification results demonstrate that the proposed method can identify surface defects effectively.

NDT of Composites Based on Active Infrared Thermography and Ultrasound Testing

2021 ◽  
Vol 70 (2) ◽  
pp. 3-6
Author(s):  
Lovre Krstulović-Opara ◽  
Petra Bagavac ◽  
Antun Božanić ◽  
Željko Domazet
Keyword(s):  
Infrared Thermography ◽  
Low Frequency ◽  
Field Method ◽  
Evaluation Methods ◽  
Material Structure ◽  
Destructive Testing ◽  
Full Field ◽  
Area Of Interest ◽  
Active Infrared Thermography ◽  
Ultrasound Testing

Composite materials, such as glass and carbon reinforced ones, are characterized by inhomogeneous structure that requires non destructive testing based on uncommon evaluation methods. The presented approach is based on the active infrared thermography, supported by the A-scan ultrasound testing. The heat wave propagation induced by halogen or xenon bulbs, due to the differences in thermal conductivity, reveals material structure and anomalies. In our previous work we have developed several signal processing and depth evaluation methods, but the real engineering approach requires additional approval testing methods such as the A-scan ultrasound is. The A-scan ultrasound, based on the low frequency probe, enables approval of anomalies located by infrared thermography. The active infrared thermography, as a full field method, enables evaluation of the whole scanned area. The A-scan, as a point-wise method, does not provide the image of whole area of interest. By combining these two methods, robust and reliable approach to analysis of composite structure is enabled.

The Added Value of Infrared Thermography to Impact Damaging Assessment of Carbon Fibre Reinforced Composites

NDT World ◽  
2016 ◽  
Vol 19 (3) ◽  
pp. 49-53
Author(s):  
Карломаньо ◽  
Giovanni Carlomagno ◽  
Монако ◽  
Ernesto Monako ◽  
Боффа ◽  
...  
Keyword(s):  
Composite Material ◽  
Infrared Thermography ◽  
Stacking Sequence ◽  
Impact Event ◽  
Imaging Device ◽  
Thermal Images ◽  
Impact Tests ◽  
Phase Images ◽  
Lock In ◽  
The Impact

Introduction. The weakness of composites to impact load is a well known problem. In particular, their impact damaging happens through complex mechanisms which are still not completely understood also because of the multitude of materials that can be created by changing: matrix, reinforcement and/or stacking sequence. It is enough to change the direction of a layer of fibres to have a new composite material. Once a new material is created, it is important to assess its performance under impact, or its impact resistance. The scope of this work is to show how advantageous may be to use infrared thermography to monitor impact tests, which are performed to ascertain the resistance-to-impact of a new composite material. Methods. Infrared thermography (IRT) and phased array ultrasonic testing (PAUT) are used. IRT is used with a twofold function: • on-line monitoring the impact event to visualize thermal signatures which bear the witness for the existence of any occurred damage; • non-destructive evaluation with lock-in thermography (LT) of the impacted specimens. Results. Some results are reported in terms of: • thermal images taken during impact tests on carbon/epoxy specimens; • phase images taken on the impacted specimens with lock-in thermography; • C-scan images taken with PAUT on the impacted surface of one specimen are compared with phase images obtained with lock-in thermography and also with thermal images taken during the impact. Discussion. Both LT and PAUT are effective in detecting the impact damage; LT is fast and more effective to map large surfaces, conversely PAUT is better to get information along the thickness especially in case of thick parts. Then, an integrated use of both techniques would be advantageous. However, they are characterized by some uncertainty in discriminating very thin delaminations when they are compared with the thermal signatures visualized during monitoring of the impact event, especially in presence of composites with complex stacking sequence. Conclusion. The obtained results show that, if the aim is to assess the performance under impact of composite materials for design purposes, monitoring the impact with an infrared imaging device appears to be the fastest and better solution.

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