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Submitted to: Computer Vision Technology for Food Quality Evaluation
Publication Type: Book / Chapter Publication Acceptance Date: 10/30/2015 Publication Date: 1/28/2016 Citation: Qin, J., Chao, K., Kim, M.S. 2016. Introduction to Raman chemical imaging technology. Computer Vision Technology for Food Quality Evaluation. 2nd edition. New York, NY: Academic Press. p.141-171. Interpretive Summary: Since the initial 1928 discovery of the Raman scattering effect, many technological advances have helped make Raman spectroscopy one of today’s most advanced optical sensing techniques. For many years, obstacles such as weak Raman signals, vulnerability to fluorescence interference, low detection efficiency, and limited data processing speeds had precluded broad use of the technique. Advances such as small diode lasers, long optical fibers, Fourier Transform Raman spectrometers, charge-coupled devices, efficient laser rejection filters, and powerful personal computers have helped conquer those barriers. Raman chemical imaging is a novel technique that equips conventional Raman spectroscopy with the capacity for spatial information acquisition. Raman chemical images can be used to visualize sample composition, spatial distribution, and morphological features of targets. This book chapter presents Raman chemical imaging technology for assessing food safety and quality. The main topics include theory of Raman scattering; measurement techniques such as backscattering and transmission Raman spectroscopy, spatially offset Raman spectroscopy, and surface-enhanced Raman spectroscopy; point-scan, line-scan, and area-scan methods of Raman image acquisition; Raman imaging instrumentation (e.g., excitation sources, wavelength separation devices, detectors, imaging systems, and calibration methods); and techniques for analyzing Raman images (e.g., image preprocessing, target identification, mapping, and quantitative analysis). Finally, examples of practical applications of the Raman chemical imaging technology for food safety and quality inspection are discussed. Technical Abstract: New developments in computer and imaging hardware have significantly advanced Raman spectroscopy and spectral imaging technologies, and have led to the recent emergence of new Raman detection techniques for rapid and online applications. This book chapter presents Raman chemical imaging technology and its use for evaluating food and agricultural products. Following an overview of the theory of Raman scattering, Raman spectroscopy measurement techniques (e.g., backscattering Raman spectroscopy, transmission Raman spectroscopy, spatially offset Raman spectroscopy, and surface-enhanced Raman spectroscopy), Raman image acquisition methods (i.e., point-scan, line-scan, and area-scan methods), Raman imaging instruments (e.g., excitation sources, wavelength separation devices, detectors, imaging systems, and calibration methods), and techniques for analyzing Raman images (e.g., image preprocessing, target identification, mapping, and quantitative analysis), illustrative examples of practical applications in food safety and quality inspection applications using Raman chemical imaging techniques are discussed. |
