Submitted to: Key Engineering Materials
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/25/2004
Publication Date: 8/17/2004
Citation: Kim, M.S., Lefcourt, A.M., Chen, Y.R., Kang, S. 2004. Hyperspectral and multispectral laser induced fluorescence imaging techniques for food safety inspection. Key Engineering Materials. Vols.270-273:PP.1055-1063. Interpretive Summary: There is a need for reliable optical sensing systems that can be employed in the food processing plants for detection of contamination due to animal feces. Our laboratory has been exploring fluorescence techniques for rapid-nondestructive detection of fecal contamination on fruits and vegetables. Researchers at the ISL have developed several imaging systems based on fluorescence techniques. These systems include hyperspectral fluorescence imaging and multispectral laser-induced fluorescence (LIF) imaging systems with multispectral capabilities. The versatility and sensitivity of the fluorescence imaging techniques for detection of fecal contamination on fruits are demonstrated with apples artificially contaminated with a range of diluted cow feces. Regions of fecal contamination that are not readily visible to human eye are easily identified in the multispectral fluorescence images. We also developed a two-band ratio as a multispectral fusion algorithm along with automated detection method for animal feces contamination on apples. Presented are sensing systems and methodologies useful to food scientists, engineers, regulatory government agencies (FSIS and FDA), and food processing industries.
Technical Abstract: Recently, we developed two imaging systems for food safety research; a laboratory-based hyperspectral imaging system capable of both reflectance and fluorescence measurements and a multispectral laser induced fluorescence imaging system. Because many contiguous spectral bands are acquired with each hyperspectral image pixel, the resulting data quantity makes uses of a hyperspectral imaging spectrometer for on-line food safety inspection impractical. Instead, the spectral and spatial information is used to determine several optimal wavebands that can be implemented using a multispectral imaging system. We present a systematic method for using hyperspectral image data to identify a few wavebands that can be used in multispectral detection systems. Also presented is a two-band ratio as a multispectral fusion method along with an automated detection application for animal feces contamination on apples. The fluorescence imaging techniques demonstrated that even minute quantities of animal feces, not clearly visible to human eye, could be detected. Practical considerations for development of multispectral fluorescence imaging systems for on-line uses are also discussed.