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United States Department of Agriculture

Agricultural Research Service

Research Project: TECHNOLOGIES FOR ASSESSING AND GRADING QUALITY AND CONDITION OF CUCUMBERS AND TREE FRUITS

Location: Sugarbeet and Bean Research

Title: Optimization of the Hyperspectral Imaging-based Spatially-resolved System for Measuring the Optical Properties of Biological Materials

Authors
item Cen, Haiyan -
item Lu, Renfu

Submitted to: Optics Express
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 20, 2010
Publication Date: August 1, 2010
Citation: Cen, H., Lu, R. 2010. Optimization of the hyperspectral imaging-based spatially-resolved system for measuring the optical properties of biological materials. Optics Express. 18(16):17412-17432.

Interpretive Summary: Optical characterization can provide useful information for assessing the chemical and structural properties of food and agricultural products. However, no effective, convenient method currently is available for measuring the optical properties (i.e., absorption and scattering) of food and agricultural products. This research was thus aimed at developing and optimizing a spatially-resolved technique for measuring the optical properties of biological materials like food and agricultural products. Several critical factors in the design of the optical property measuring system, including reference measurement, light beam and source-detector distance, and system performance, were examined and optimized via computer simulations and experimental tests on model samples of known optical properties. Results demonstrated that the light beam and source-detector distances needed to meet specific requirements for accurate measurement of the optical properties. The optimized optical property measuring system had average measurement errors of 23% for the absorption coefficient and 7% for the scattering coefficient, which are comparable to, or better than, reported studies. This research provides an important guide in the development and optimization of spatially resolved technique for measuring the optical properties of biological materials. The technique will be valuable for optical characterization and quality evaluation of food and agricultural products.

Technical Abstract: This paper reports on the optimization and assessment of a hyperspectral imaging-based spatially-resolved system for determination of the optical properties of biological materials over the wavelengths of 500-1,000 nm. Twelve model samples covering a wide range of absorption and reduced scattering coefficients were created to validate the hyperspectral imaging system, and their true values of absorption and reduced scattering coefficients were determined and then cross-validated using three commonly used methods (i.e., transmittance, integrating sphere, and empirical equation). Light beam and source-detector distance were optimized through Monte Carlo simulations and experiments for the model samples. The optimal light beam should be of Gaussian type with the diameter of less than 1 mm, and the optimal minimum and maximum source-detector distance should be 1.5 mm and 10-20 mean free paths, respectively. The optimized hyperspectral imaging-based spatially-resolved system achieved good estimation of the optical parameters for the model samples.

Last Modified: 8/1/2014
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