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Semiconductor Laser Multi-Spectral Sensing and Imaging
Photonic Device and System Lab, Department of Electrical and Computer Engineering, D2-N318, University of Houston, 4800 Calhoun, Houston, TX 77204-4005, USA
Labsphere, Inc. 231 Shaker Street, North Sutton, NH 03260, USA
* Author to whom correspondence should be addressed.
Received: 23 November 2009; in revised form: 14 December 2009 / Accepted: 5 January 2010 / Published: 13 January 2010
Abstract: Multi-spectral laser imaging is a technique that can offer a combination of the laser capability of accurate spectral sensing with the desirable features of passive multispectral imaging. The technique can be used for detection, discrimination, and identification of objects by their spectral signature. This article describes and reviews the development and evaluation of semiconductor multi-spectral laser imaging systems. Although the method is certainly not specific to any laser technology, the use of semiconductor lasers is significant with respect to practicality and affordability. More relevantly, semiconductor lasers have their own characteristics; they offer excellent wavelength diversity but usually with modest power. Thus, system design and engineering issues are analyzed for approaches and trade-offs that can make the best use of semiconductor laser capabilities in multispectral imaging. A few systems were developed and the technique was tested and evaluated on a variety of natural and man-made objects. It was shown capable of high spectral resolution imaging which, unlike non-imaging point sensing, allows detecting and discriminating objects of interest even without a priori spectroscopic knowledge of the targets. Examples include material and chemical discrimination. It was also shown capable of dealing with the complexity of interpreting diffuse scattered spectral images and produced results that could otherwise be ambiguous with conventional imaging. Examples with glucose and spectral imaging of drug pills were discussed. Lastly, the technique was shown with conventional laser spectroscopy such as wavelength modulation spectroscopy to image a gas (CO). These results suggest the versatility and power of multi-spectral laser imaging, which can be practical with the use of semiconductor lasers.
Keywords: multispectral; laser sensing; laser imaging; spectral imaging; spectroscopy; chemical detection; semiconductor lasers; mid-infrared lasers
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Cite This Article
MDPI and ACS Style
Le, H.Q.; Wang, Y. Semiconductor Laser Multi-Spectral Sensing and Imaging. Sensors 2010, 10, 544-583.
Le HQ, Wang Y. Semiconductor Laser Multi-Spectral Sensing and Imaging. Sensors. 2010; 10(1):544-583.
Le, Han Q.; Wang, Yang. 2010. "Semiconductor Laser Multi-Spectral Sensing and Imaging." Sensors 10, no. 1: 544-583.