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NIST RESEARCHERS TAP INTO ADVANCED PHOTON SOURCE FOR X-RAY
"EYES"
A team of scientists at the National Institute of Standards
and Technology, drawing on the Advanced Photon Source (APS)
at Argonne National Laboratory, has developed a powerful technology
for the detection of tiny voids, cracks, and otherwise undetectable
microstructural details three-dimensionally in materials including
metals, ceramics, and biological specimens.
USAXS yields plots of data points that correspond to angles
and intensities of the scattered electrons. These graphed
curves can be organized from different perspectives into high-resolution
three-dimensional pictures.
For more information, contact Mark Bello at (301) 975-3776;
mark.bello@nist.com.
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TECHNOLOGY OF THE MONTH: VEHICLE IDENTIFICATION AND NUMBER-PLATE
READER
Even with the increasing number of vehicles currently on
the road, it is now possible to identify a vehicle, the manufacturer,
make, and model, and also to read the number plate.
The automatic number plate reader provides the image of the
front of the vehicle and the position of the number plate
within the image. The following processing tasks are performed.
The attitude of the vehicle with respect to the camera is
estimated, using knowledge of the camera deployment, including
its focal length, pitch and roll angles, and the position,
size and orientation of the number plate within the image.
The 2D positions within the image of features of interest,
such as the manufacturer's logo or the direction indicator
lights, are extracted. 3D measurement estimates are obtained
from the 2D image feature positions using the estimate of
the vehicle attitude, knowledge of deployment, and assumptions
regarding symmetry of the vehicle design.
The 3D vehicle estimates can be matched with a database containing
3D measurements from known vehicle types in order to determine
the type of vehicle. The benefits of this approach are that
the database is independent of the deployment, the system
requires a single camera only, and 3D information is utilized
to provide high recognition performance. The device's commercial
viability is proven and in use, and patents are pending.
Get
the complete report; e-mail: nasatech@yet2.com;
phone: 617-557-3837.
The Technology of the Month describes inventions available
for license through the yet2.com marketplace. Search over
$2.5 billion of licensable technologies at www.nasatech.com/techsearch.
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A MULTIFUNCTIONAL SPECTRAL ANALYZER WITH MANY ADVANTAGES
At NASA's Jet Propulsion Laboratory a group of researchers
is developing a multifunctional active-excitation spectral
analyzer (MAESA) that will be highly sensitive, low in power
consumption and noise, and will span the wavelength range
from 0.5 to 2.5 micrometers. It would also be portable and
would operate near room temperature.
The MAESA would include a laser and associated optics for
generating a beam of monochromatic light to illuminate a point
or a line on a target. Other optics would image the target
onto a rectangular focal plane array of InGaAs photodetectors.
At the target, the illumination would excite Raman scattering,
the spectrum of which would depend on the chemical composition
of the target. The light returning from the target would be
long- wavelength-filtered to remove the laser wavelength component,
then focused onto a convex diffraction grating, which would
spectrally disperse the remaining Raman-scattered light along
a row of the array. The wavelength of the spectral component
impinging on the pixels of the array would be a known function
of the position of the pixel along the row.
Read the entire brief on page 14a of the Photonics Tech Briefs
supplement to the January 2002 issue of NASA Tech Briefs.
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A ULTRAVIOLET LASER FOR HIGH FIBER BRAGG GRATING YIELDS
For the successful production of high-quality fiber Bragg
gratings for use in a variety of telecommunication devices,
beam quality is a top consideration. Oxford
Lasers Inc. says it is adding the FBG Ultra to its line
of fast, cost-effective, round-the- clock UV lasers for use
in producing gratings. Oxford says the Ultra has a beam diameter
of 2 mm with point stability of better than 0.01 mrad per
degree C. A long temporal coherence length of 40 mm enables
flexibility in writing processes and means that the gratings
can be produced by both phase-mask and holographic techniques.
Oxford says it has designed the Ultra as a reliable industrial
tool for the high-volume production of gratings, adding that
it is suited for production in standard telecomm fiber, hydrogen-free
fiber, multimode and multicore fibers, and planar waveguides.
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