Peer-Reviewed Articles
705
3D Reconstruction Methods Based on the Rational Function Model
C. Vincent Tao and Yong Hu
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Full Article
The rational function model (RFM) is an alternative sensor model
allowing users to perform photogrammetric processing. The RFM has
been used
as a replacement
sensor model in some
commercial photogrammetric systems due to its capability of maintaining the
accuracy of the physical sensor models and its generic characteristic
of supporting sensor-independent
photogrammetric processing. With RFM parameters provided, end users
are able
to perform photogrammetric processing including ortho-rectification, 3D reconstruction,
and DEM
generation with an absence of the physical sensor model. In this research,
we investigate two methods for RFM-based 3D reconstruction, the
inverse RFM method
and the forward RFM
method. Detailed derivations of the algorithmic procedure are described. The
emphasis is placed on the comparison of these two reconstruction methods. Experimental
results show that
the forward RFM can achieve a better reconstruction accuracy. Finally, real
Ikonos stereo pairs were employed to verify the applicability and
the performance of
the reconstruction
method.
715 Updating Solutions of the Rational Function
Model Using Additional Control Information
Yong Hu and C. Vincent Tao
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Full Article
The rational function model (RFM) is a sensor model that allows users
to perform ortho-rectification and 3D feature extraction from imagery
without knowledge
of the physical sensor model. It is a fact that the RFM is determined by
the vendor using a proprietary physical sensor model. The accuracy
of the RFM solutions
is dependent on the availability and the usage of ground control points (GCPs).
In order to obtain a more accurate RFM solution, the user may be asked to
supply GCPs to the data vendor. However, control information may
not be available
at the time of data processing or cannot be supplied due to some reasons
(e.g., politics or confidentiality). This paper addresses a means
to update or improve
the existing RFM solutions when additional GCPs are available, without knowing
the physical sensor model. From a linear estimation perspective, the above
issue
can be tackled using a phased estimation theory. In this paper, two methods
are proposed: a batch iterative least-squares (BILS) method and an incremental
discrete
Kalman filtering (IDKF) method. Detailed descriptions of both methods are
given. The feasibility of these two methods is validated and their
performances are
evaluated. Some results concerning the updating of Ikonos imagery are also
discussed.
725 Satellite Monitoring of Urban Spatial Growth
in the Atlanta Metropolitan Area
Xiaojun Yang
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Full Article
Monitoring growth and change along the metropolitan periphery is
of critical concern both to those who study metropolitan dynamics
and those who must manage
resources and provide services in these rapidly changing environments. This
research has been directed to assess urban spatial growth and land
change along the outskirts
of Atlanta, one of the fastest growing metropolitan areas in the United States
in the past three decades. A time series of satellite images was used to trace
the development of urban land uses for the period of 1973 to the present. An
image processing and GIS-based method was developed to achieve the research
goal. Results reveal that every week, more than one-hundred acres
of forest, green
space, and farmland in the Atlanta region were converted into urban uses. Between
1973 and 1999, the urban territorial extent has expanded by 247 percent for
13 metro counties while the population increased by 96 percent.
The rate of urban
growth was much higher in outer suburban counties. Concomitant with this high
rate of urban growth was a far-reaching evolution in Atlanta's urban spatial
form. The growth of high-density urban use (mainly commercial, transportation,
industrial, and high-rise residential) is found to experience a clear transition
from linearly concentrated form towards a multinucleated pattern. The spread
of low-density urban use (mainly residential) exhibited a widely dispersed
pattern, thus indicating a major feature of the suburbanization.
In addition, Atlanta
has few physical barriers to urban development; this growth in urban physical
extent seems to be unlimited as the population and business continue to grow,
particularly in the outer suburbs.
735 Using GIS to Assess and Manage the Conservation
Reserve Program in Finney County, Kansas
J. Wu, M.D. Ransom, M.D. Nellis, G.J. Kluitenberg, H.L. Seyler, and B.C.
Rundquist
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Full Article
The 1985 U.S. Conservation Reserve Program (CRP) was modified in
the 1996 Farm Bill, which authorized a total enrollment of up to
14.8 million ha, an early
termination of certain CRP contracts, and additional new enrollments. This
study used soil, land-use, groundwater, and other environmental
layers from currently
available sources of information for Finney
County, Kansas. By using a geographic information system (GIS), we found that
aquifer thickness, coinciding with gas or oil fields, was closely associated
with the distribution of CRP
land while other factors such as soil, aquifer depth, physiography, or slope
had little effect on the CRP. We generated a map that outlined those CRP lands
eligible for early termination. By using the state soil geographic database
to designate the conservation priority areas and soil erosion index
as the criterion
to rank potential CRP lands, we created another map showing areas best suited
for new CRP bids.
745 Underwater Digital Stereo-Obesrvation Technique
for Red Hydrocoral Study
A.K. Chong and P. Stratford
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Full Article
A linear regression model is used to determine the size of correction
required for stereophotogrammetric measurement from photographs taken
in an underwater
environment. The
model utilizes the stereophotogrammetric distance measurement of an object
from a set of object-space control points. A correction factor is applied to
the stereophotogrammetric
measurement to obtain the corrected measurement. The technique was used to
study the growth of an endemic species of hydrozoan coral, Errina novaezelandiae,
in
Doubtful Sound,
Fiordland, New Zealand. The results show that the technique has a measurement
accuracy of ±1.2 mm at the 95 percent confidence level. We found that
these hydrozoan corals have
a high erosion rate, presumably due to grazing, which was not reported previously.
753
A Rigorous Technique for Forensic Measurement of Surveillance Video Footage
A.K. Chong
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Full Article
A technique using a mono-view video frame to make accurate measurement
of physical features of a crime suspect is discussed. The technique
uses a portable
control
frame to calibrate the surveillance video cameras lens in situ. The control
frame is also used to provide object-space control for the computation
of exterior orientation parameters of the photography. The technique
removes
lens distortion,
x-tilt, y-tilt, and PPA offset from the video frame coordinates. Surveillance
video camera lens calibration and the laboratory testing of the technique
are discussed in detail. In addition, an argument is provided to examine
the uncertainties
in the forensic measurement using mono-view video footage. A case study
involving a short clip of bank surveillance video footage is used
to demonstrate the
use
of this technique in a photogrammetrically unfriendly situation. Trials
show that height measurement accuracy using this technique exceeds
the police
specification of 30 mm for a suspect standing upright.
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