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Bi-directional Effect on A Multi-spectral Imaging Sensor for Crop Nitrogen Assessment

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Paper number  023010,  2002 ASAE Annual Meeting . (doi: 10.13031/2013.9610) @2002
Authors:   Yunseop Kim, John F. Reid
Keywords:   Spectral analysis, image processing, nitrogen, precision agriculture

Development of an N management system potentially allows producers to reach their production goals, while minimizing the effects on the environment. This paper reports on the analysis of the bi-directional effect to a vision-based reflectance sensor for assessing N status of corn canopies. Nitrogen status of the crop was estimated by determining the reflectivity of crop canopy from the image. Solar zenith angle varies over daytime and generates the nonlinearity in reflectance measurement. Data represented the change of solar position and nonlinearity of reflectance. Compensation algorithm was applied to correct for non-linearity of the reflectance response. The compensated reflectance was consistent against the varying solar zenith angle throughout the daytime, when testing with a known reflectance panel.

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