PNNL-13501 - Pacific Northwest National Laboratory

Figures 3 and 4 illustrate the impact of that uncertainty on
modeled geometry. We observed severe distortion in the
PhotoModeler and FotoG objects. A biased elevation
distortion was evident in the FotoG site model that has
objects either under (southwest end) or above (northeast
end) the surface of what in actuality is a very flat dry lake
bed. This feature, using a geometric primitive to
constrain the photogrammetrically derived geometry, is
the core of the hybrid geometry- and image-based sitemodeling
approach described below.
Figure 3. Partial three-dimensional model of the HAZMAT
Spill Center constructed and photo-rendered with
PhotoModeler Pro—although line/face continuity for
constructing objects is easily maintained during on-screen
construction, geometric distortion cannot be controlled.
Model geometry can be exported to computer aided design.
Figure 4. Partial three-dimensional model of the HAZMAT
Spill Center constructed and rendered in AutoCAD from
linked FotoG-FMS—geometry can be constructed only from
points, single lines (not polylines), and cylinders, so
construction of faces and objects must be done in AutoCAD
after point/line/cylinder generation from the imagery.
Geometry here again is distorted; the ground surface is
effectively flat, so the features should “sit” on it, the trailer
should be rectangular and square, etc. Rendering of this
model with photographs must be done in a separate
visualization program such as 3D Studio.
Hybrid Geometry- and Image-Based System. Debevec
(1996) and Debevec et al. (1996) described a hybrid
geometry- and image-based approach to “creating realistic
synthetic views of existing architectural scenes from a
sparse set of still photographs.” This approach, similar in
principle (but much more sophisticated) to that used by
RapidScene for National Technical Means imagery,
depends on fitting geometric primitives (rectangular
planes, boxes, pyramids, etc.) to features in the
photographs, and using knowledge of those shapes to
assist in photogrammetric calculations and determining
overall site geometry.
Expansion of this approach to use genetically meaningful
primitives representing weapons process components, and
to allow creation in computer aided design of site features
similar to the geometry-based approaches, would make it
the system-of-choice for site-modeling applications. This
object-based approach would provide a basis for
hyperlinking (e.g., Feiner et al. 1995) with object-based
site three-dimensional computer aided design templates
and all other sources of information.
Ground-Truth Sensor Development and Demonstration
We developed and demonstrated an improved groundtruth
chemical sensor, as well as the associated analysis
software for determination of nuclear, biological,
chemical-type weapons. To this end, a commercial
Fourier-transform infrared spectroscopy was obtained and
employed for proliferation determination using passive
infrared sensing. We transported its spectrometer and
ancillary detection equipment to the Nevada test site for
data measurement and acquisition, and have subsequently
analyzed the data via introduction of a graphical user
interface software package for data reduction.
The Owl 2000 campaign for remote detection of chemical
signatures was carried out at the test range under the
auspices of LLNL. The campaign consisted of
monitoring a number of controlled releases from the
HAZMAT Spill Center and test range stacks (see
Figure 1) by several ground-sensing techniques as well as
from two airborne platforms (General Dynamics H-57
“Canberra” and DeHavilland DHC-6 “Twin Otter”
aircraft). Our Laboratory’s chemical remote sensing
system consisted primarily of a Midac model M2401-C
emission interferometer; the Midac FTIR was equipped
with ZnSe optics and a mercury-cadmium-telluride
detector with spectral response to 16 µm in the long-wave
infrared. The infrared data were augmented by
meteorological data from the test site, as well as stack and
background temperatures and estimated flow release rates
for the release species under investigation.
In addition to the measurement campaign, the software
for chemical retrieval information has been under
development and continues to undergo further refinement.
Sensors and Electronics 395