Stress-detection Lenses
NASA and other organizations have conducted extensive research
on early detection of stress in vegetation through use of various
sensory devices that measure radiations emitted or reflected
by plants. An extension of that technology is a simple, inexpensive
home garden variety plant stress detector, a pair of rose-tinted
lenses that enable a viewer to see otherwise invisible signs
of plant deterioration. Known as Hawkeye Lenses, the glasses
are marketed by Optical Sales Corporation, Portland, Oregon;
they incorporate technology developed by a NASA scientist-Dr.
Leonard A. Haslim of Ames Research Center-and they were introduced
to the commercial market through the technology transfer efforts
of the Ames Commercial Technology Office.
Hawkeye lenses enable a viewer to see otherwise invisible
signs of plant deterioration.
The Hawkeye lenses serve as a "passive chlorophyll detector."
When drought, pests, disease or other agents cause stress to
a plant by reducing chlorophyll, the initial plant damage is
not visible to the naked eye except under a microscope. The lenses
make it visible by means of dyes, integrated into the lenses,
that filter out certain wavelengths of light.
When one looks at a green leaf through a Hawkeye lens, the
stressed part of the leaf is visually enhanced and it stands
out from the healthy part of the plant by appearing pink or brownish
red. "The filtering lenses provide a color discrimination
due to the way plants absorb and reflect sunlight," explains
Dr. Robert Brock, president of Optical Sales Corporation.
The glasses sell for less than $100 and can be made into prescription
glasses. "The glasses work because they enhance the edges
of the visual spectrum, allowing the user to see what normally
can't be seen," Brock adds. "Plant stress becomes visible
earlier, at a critical stage when something can often be done."
Optical Sales Corporation is continuing stress detection research
under a Department of Agriculture contract; among the researchers
is Dr. Carlos Blazquez of the University of Florida, who has
worked with NASA in infrared detection of stress in Florida's
citrus groves. The advanced phase of the research is aimed at
refining the technology and tailoring it to match the light spectra
reflected by various specific plant types.
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