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Optics Express

Optics Express

  • Editor: Michael Duncan
  • Vol. 14, Iss. 25 — Dec. 11, 2006
  • pp: 12485–12493

Non-contact laser spectroscopy for plant discrimination in terrestrial crop spraying

Kaveh Sahba, Sreten Askraba, and Kamal E. Alameh  »View Author Affiliations

Optics Express, Vol. 14, Issue 25, pp. 12485-12493 (2006)

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The early development of a novel micro-photonic based sensing architecture for use in selective herbicide spraying systems performing non-contact spectral reflectance measurements of plants and soil in real time has been described. A combination module allows three laser diodes of different wavelengths to sequentially emit identically polarized light beams through a common aperture, along one optical path. Each exiting beam enters an optical structure which generates up to 14 parallel laser beams. A pair of combination modules and optical structures generates 28 beams over a 420mm span which illuminates the plants from above. The intensity of the reflected light from each spot is detected by a high speed line scan image sensor. Plant discrimination is based on analyzing the Gaussian profile of reflected laser light at distinguishing wavelengths. Two slopes in the spectral response curves from 635nm to 670nm and 670nm to 785nm are used to discriminate different plants. Furthermore, by using a finely spaced and collimated laser beam array, instead of an un-collimated light source, detection of narrow leaved plants with a width greater than 20mm is achievable.

© 2006 Optical Society of America

OCIS Codes
(120.0280) Instrumentation, measurement, and metrology : Remote sensing and sensors
(150.3040) Machine vision : Industrial inspection
(200.4560) Optics in computing : Optical data processing
(300.6360) Spectroscopy : Spectroscopy, laser

ToC Category:

Original Manuscript: September 21, 2006
Revised Manuscript: November 20, 2006
Manuscript Accepted: November 25, 2006
Published: December 11, 2006

Virtual Issues
Vol. 2, Iss. 1 Virtual Journal for Biomedical Optics

Kaveh Sahba, Sreten Askraba, and Kamal E. Alameh, "Non-contact laser spectroscopy for plant discrimination in terrestrial crop spraying," Opt. Express 14, 12485-12493 (2006)

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