Astronomical instrument adapted for down-to-earth studies (Forwarded)

University Communications
New Mexico State University
Las Cruces, New Mexico

May 8, 2006

Astronomical instrument adapted for down-to-earth studies
By Karl Hill

Imaging technology originally developed by NASA to study planets and stars
is being focused on down-to-earth subjects -- including insects and dust
devils -- by New Mexico State University researchers.

NMSU astronomer Nancy Chanover often uses a hyperspectral imaging system
mounted on a telescope to study planetary atmospheres. Now she has teamed up
with David Voelz of NMSU's Klipsch School of Electrical and Computer
Engineering to build a portable version that could be used in a wide range
of applications, from remote sensing of agricultural crops to the study of
weather phenomena.

The imaging system is built around an acousto-optic tunable filter (AOTF),
which allows the camera to take images of an object at many different
wavelengths of light without having to change filters. In astronomy, these
images can provide a wealth of knowledge about a planet's atmosphere,
because elements of the atmosphere can be identified by their "spectral
signatures," or the way they reflect or absorb light at different
wavelengths across the spectrum.

Jeff Drake of NMSU's Entomology, Plant Pathology and Weed Science Department
is betting that different types of insects also have distinctive spectral
signatures, and he is collaborating with Chanover and Voelz to find out. The
goal is a quick and accurate way to determine what insects are present in a
field, and the ratio of beneficial insects to pests.

For about three years, Drake has been working on an automated insect
identification system to help farmers determine how much pesticide to use on
crops. Often, he said, there are enough beneficial insects present in a
field to control the harmful insects without applying pesticides, but
farmers can't risk the time it takes to find out.

"The traditional method is to count by hand," he said. "Typically you use an
Insectavac to get four 100-foot-row samples and that might generate 10,000
or more insects. It can take weeks to count them."

Drake's efforts to date have used a digital camera to photograph insect
samples and a computer software program to analyze the images and identify
insects by their shape and size.

"We've been able to get about 95 percent accuracy at the genus level," he
said. "One of the drawbacks is that plant material can get classified as
insects by size and shape."

With spectral images of insect samples made by Chanover and Voelz, Drake
will determine whether insects can be differentiated by their spectral
signatures, which could be the key to a rapid and highly accurate automatic
identification system.

In another field test planned for this spring, the researchers will take the
portable imaging system -- dubbed PHIL for Portable Hyperspectral Imaging
Laboratory -- out on the Jornada Experimental Range northeast of Las Cruces
to try to capture spectral images of dust devils. Jim Murphy, head of NMSU's
Astronomy Department, is collaborating on that experiment, which could prove
useful in the design of future explorations on Mars. Murphy, whose research
interest is planetary meteorology, has been a member of spacecraft
instrument teams for several NASA missions to Mars, which is notorious for
its dust storms.

"The hardware is far enough along that we can do these kinds of tests and
trials," Voelz said. "We haven't used the camera out in the dirt before.
Part of our work is to figure out how to make it more portable, rugged and
robust."

In the meantime, Chanover continues to use a telescope-mounted AOTF camera
in her planetary studies. The system was mounted on the 3.5-meter telescope
at Apache Point Observatory last June for a study of Uranus. Next she plans
to use it to analyze the atmosphere of Jupiter.

"Having images of planetary atmospheres in a huge number of wavelengths can
tell you so many things," she said. "One application that we're trying to
push forward is identifying the compounds that are coloring the atmosphere
of Jupiter. That is an outstanding mystery in giant planet studies -- we
really don't know what makes the Red Spot red."

The NMSU group has a lab filled with about a half million dollars' worth of
instruments and equipment provided by NASA's Goddard Space Flight Center
(GSFC). When GSFC shifted away from instrument building, the contents of its
instrument lab were shipped to Las Cruces with the expectation that the NMSU
group would carry forward the camera development work. Chanover, who earned
her Ph.D. in astronomy at NMSU, was a postdoctoral researcher at GSFC before
returning to NMSU as a faculty member in 1998.

With the NASA equipment the NMSU collaborators currently are developing two
AOTF cameras, one for telescope studies and the portable one for near-field
imaging.

"We haven't done full calibrations yet and we don't know all of their
idiosyncrasies, but we're far enough along that we can push the
instrumentation work while also making discoveries with them," Voelz said.

The project, which originated in the university's Space and Aerospace
Research Cluster, is an example of the kind of cross-disciplinary
collaboration the cluster approach is intended to foster.

IMAGE CAPTION:
[http://ucommphoto.nmsu.edu/newsphoto...anover_lab.jpg (788KB)]
NMSU researchers Nancy Chanover, left, and David Voelz are building a
portable hyperspectral imaging camera with a wide range of potential uses.
(NMSU photo by Victor Espinoza)