February 4 2007
Home -- R&D Hom
AVIRIS scene of St. Louis Bay, Mississippi
Imaging Spectrometers gather data over a wide band of the electromagnetic spectrum
in many small bandpass channels. Such data (often called hyperspectral data) can be
used to accurately determine the composition of the ground cover in a scene. When the
images are acquired at high spatial resolution, the resulting data provide a robust
characterization of the earth's surface. The scene above is a 4 meter resolution, 3
channel composite of Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data
taken over the entrance to St. Louis Bay, Mississippi. The pronounced linear feature at
scene center is the railway bridge joining Bay St. Louis and Pass Christian. The bridge
is approximately 1.7 nautical miles in length.
AVIRIS
The high quality of this image clearly illustrates the usefulness of hyperspectral data for
high resolution mapping purposes. These data were acquired in October of 1998 as part
of a collaboration between NOAA/NOS/NGS and the NASA/Jet Propulsion Laboratory
(JPL) to deploy the AVIRIS instrument in a NOAA Twin Otter aircraft. Hyperspectral
datasets of this quality were flown both in 1998 and 1999 to support a wide range of
experiments by researchers throughout the remote sensing community. At NGS, we
have experiments underway to explore the use of these data for shoreline mapping,
coastal change detection, and airport obstruction charting.
The deployment of AVIRIS in a NOAA twin otter was the first low altitude operational
use of this sensor. AVIRIS data from these experiments have spatial resolutions on the
order of 4 meters, but some scenes with 2 meter resolution have been acquired. The
integration of GPS and inertial navigation technologies with the image data enables JPL
engineers to construct the high quality scenes. In the photo at below left, the NOAA
pilot and JPL AVIRIS system operator are shown alongside the Twin Otter aircraft at
Harrisburg, PA airport. The right photo shows the installation of AVIRIS in the Twin Otter
camera bay.
NOAA Twin Otter Aircraft
AVIRIS Installation
The scenes below are 3 channel composites of the calibration range at the NASA
Stennis Space Center in Stennis, Mississippi. The left image has a nominal resolution of
2.1 meters. The right image was flown on the same flight path at higher altitude and has
a nominal resolution 4.0 meters. Inspection of the fan array on the two scenes provides
a visible interpretation of how spectra are mixed in larger pixel sizes, and shows the
desirability of high geometric resolution for both precise location and identification of
targets in the hyperspectral cube.
2 meter scene of Stennis Space Center
4 meter scene of Stennis Space Center
Field spectrometers are used to acquire ground level spectral signatures that can be
used to remove atmospheric effects and provide ground truth for classification of the
airborne hyperspectral scenes. The photo shows a NOAA engineer gathering ground
radiance data. The plot shows radiance data for the runway asphalt and white center
line stripes at Harrisburg International Airport.
Spectral data collection at Harrisburg Airport, PA
Spectral Plot
See more information about the Harrisburg, Pennsylvania project.
See more information on the NOAA/NASA/JPL collaboration.
Coastal and Inland waters: chlorophyll, plankton, dissolved organics,
sediments, bottom composition, bathymetry...
true color image of Keywest, Florida.