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Sensors 2011, 11(8), 7773-7798; doi:10.3390/s110807773

A Review of Optical NDT Technologies

1,2,* , 3
1 School of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China 2 School of Electrical, Electronic and Computer Engineering, Newcastle University, Newcastle NE1 7RU, UK 3 School of Instrument Science and Opto-Electronics Engineering, Hefei University of Technology, Hefei 230009, China
* Author to whom correspondence should be addressed.
Received: 1 July 2011 / Revised: 1 August 2011 / Accepted: 2 August 2011 / Published: 8 August 2011
(This article belongs to the Section Physical Sensors)


Optical non-destructive testing (NDT) has gained more and more attention in recent years, mainly because of its non-destructive imaging characteristics with high precision and sensitivity. This paper provides a review of the main optical NDT technologies, including fibre optics, electronic speckle, infrared thermography, endoscopic and terahertz technology. Among them, fibre optics features easy integration and embedding, electronic speckle focuses on whole-field high precision detection, infrared thermography has unique advantages for tests of combined materials, endoscopic technology provides images of the internal surface of the object directly, and terahertz technology opens a new direction of internal NDT because of its excellent penetration capability to most of non-metallic materials. Typical engineering applications of these technologies are illustrated, with a brief introduction of the history and discussion of recent progress.
Keywords: optical non-destructive testing (NDT); speckle; endoscopic; infrared thermography; terahertz (THz) technology optical non-destructive testing (NDT); speckle; endoscopic; infrared thermography; terahertz (THz) technology
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Zhu, Y.-K.; Tian, G.-Y.; Lu, R.-S.; Zhang, H. A Review of Optical NDT Technologies. Sensors 2011, 11, 7773-7798.

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