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Proceedings Paper

Reflectance calibration of focal plane array hyperspectral imaging system for agricultural and food safety applications
Author(s): Kurt C. Lawrence; Bosoon Park; William R. Windham; Chengye Mao; Gavin H. Poole
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Paper 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.

Paper Details

Date Published: 17 March 2003
PDF: 11 pages
Proc. SPIE 4879, Remote Sensing for Agriculture, Ecosystems, and Hydrology IV, (17 March 2003); doi: 10.1117/12.462427
Show Author Affiliations
Kurt C. Lawrence, USDA/Agricultural Research Service (United States)
Bosoon Park, USDA/Agricultural Research Service (United States)
William R. Windham, USDA/Agricultural Research Service (United States)
Chengye Mao, Gatan, Inc. (United States)
Gavin H. Poole, Institute for Technology Development (United States)

Published in SPIE Proceedings Vol. 4879:
Remote Sensing for Agriculture, Ecosystems, and Hydrology IV
Manfred Owe; Guido D'Urso; Leonidas Toulios, Editor(s)

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