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Proceedings Paper

Red/near-infrared reflectance sensor system for detecting plants
Author(s): Kenneth Von Bargen; George E. Meyer; David A. Mortensen; Steven J. Merritt; David M. Woebbecke
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Paper Abstract

Growing plants, soil types, and surfaces and residues on a soil surface have distinct natural light reflectances. These reflectance characteristics have been determined using current spectroradiometry technology. Detection of plants is possible based upon the distinct reflectance characteristics of plants, soil, and residues. An optical plant reflectance sensor was developed which utilizes a pair of red and near infrared sensitive photodetectors to measure the radiancy from the plant and soil. Another pair of sensors measures radiancy from a highly radiant reference surface to accommodate varying intensities of the natural light. The ratio of the target and reference radiancies is the target reflectance. Optical filters were used to select the spectral bandwidth sensitivities for the red and NIR photodetectors. The reflectance values were digitized for incorporation into a normalized difference index in order to provide a stronger indication that a live plant is present within the field of view of the sensor. This sensor system was combined with a microcontroller for activating a solenoid controlled spray nozzle on a single unit prototype spot agricultural sprayer.

Paper Details

Date Published: 12 May 1993
PDF: 8 pages
Proc. SPIE 1836, Optics in Agriculture and Forestry, (12 May 1993); doi: 10.1117/12.144032
Show Author Affiliations
Kenneth Von Bargen, Univ. of Nebraska/Lincoln (United States)
George E. Meyer, Univ. of Nebraska/Lincoln (United States)
David A. Mortensen, Univ. of Nebraska/Lincoln (United States)
Steven J. Merritt, Univ. of Nebraska/Lincoln (United States)
David M. Woebbecke, Univ. of Nebraska/Lincoln (United States)

Published in SPIE Proceedings Vol. 1836:
Optics in Agriculture and Forestry
James A. DeShazer; George E. Meyer, Editor(s)

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