Reflectance calibration of focal plane array hyperspectral imaging system for agricultural and food safety applications

Kurt C. Lawrence; Bosoon Park; William R. Windham; Chengye Mao; Gavin H. Poole

doi:10.1117/12.462427

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17 March 2003 Reflectance calibration of focal plane array hyperspectral imaging system for agricultural and food safety applications

Kurt C. Lawrence, Bosoon Park, William R. Windham, Chengye Mao, Gavin H. Poole

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Proceedings Volume 4879, Remote Sensing for Agriculture, Ecosystems, and Hydrology IV; (2003) https://doi.org/10.1117/12.462427
Event: International Symposium on Remote Sensing, 2002, Crete, Greece

Abstract

A method to calibrate a pushbroom hyperspectral imaging system for "near-field" applications in agricultural and food safety has been demonstrated. The method consists of a modified geometric control point correction applied to a focal plane array to remove smile and keystone distortion from the system. Once a FPA correction was applied, single wavelength and distance calibrations were used to describe all points on the FPA. Finally, a percent reflectance calibration, applied on a pixel-by-pixel basis, was used for accurate measurements for the hyperspectral imaging system. The method was demonstrated with a stationary prism-grating-prism, pushbroom hyperspectral imaging system. For the system described, wavelength and distance calibrations were used to reduce the wavelength errors to <0.5 nm and distance errors to <0.01mm (across the entrance slit width). The pixel-by-pixel percent reflectance calibration, which was performed at all wavelengths with dark current and 99% reflectance calibration-panel measurements, was verified with measurements on a certified gradient Spectralon panel with values ranging from about 14% reflectance to 99% reflectance with errors generally less than 5% at the mid-wavelength measurements. Results from the calibration method, indicate the hyperspectral imaging system has a usable range between 420 nm and 840 nm. Outside this range, errors increase significantly.

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Kurt C. Lawrence, Bosoon Park, William R. Windham, Chengye Mao, and Gavin H. Poole "Reflectance calibration of focal plane array hyperspectral imaging system for agricultural and food safety applications", Proc. SPIE 4879, Remote Sensing for Agriculture, Ecosystems, and Hydrology IV, (17 March 2003); https://doi.org/10.1117/12.462427

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