Image Processing Reference
In-Depth Information
7.3
Evolution of Urban Remote Sensing and a Gallery
of Applications
With the advent of digital imaging and soft-copy photogrammetric techniques, the
number, variety, and nature of remote sensing applications have increased tremen-
dously. For example, the commercial availability of high spatial resolution imagery
(primarily in panchromatic mode) has led to developments of image processing tech-
niques targeting the improvement of coarse spatial resolution imagery. As detailed
in Chapter 11, one way of achieving this is by image fusion techniques allowing the
preservation of spectral detail in coarse resolution imagery and improvement of their
spatial resolution (Ranchin et al.
2001
). Additionally, the complexity and dynamics
of urban environments often necessitate the use of multi-sensor, multi-resolution
data sets, eventually leading to the use of data compression techniques such as prin-
cipal component analysis (PCA), spatial filtering, and image transforms in the wavelet
domain (Donnay et al.
2001
). As a result, a number of image processing and analysis
techniques have been tailored for implementation into efficient urban remote sensing
analysis, resulting in broader and more diverse applications.
7.3.1
Early Urban Remote Sensing (1950-1970)
This section presents a chronological overview of urban remote sensing applica-
tions from 1950 to 1970. This is primarily a review of typical applications that
utilized film-based systems (prior to the launch of the Landsat satellites), and were
dominated by studies of urban and infrastructure development.
Studies of urban places using remotely sensed data can be found in the journal
of Photogrammetric Engineering (now titled Photogrammetric Engineering and
Remote Sensing) as far back as the second volume published in 1936. An annotated
bibliography compiled by Chardon and Schwertz
(
1972
) and leading remote sensing journals reveals
that between 1950 and 1970, remote sensing
researchers concerned with urban applications
mostly published results from exploratory analysis of
the potential of airborne remote sensing for the study
of urban environments and specific urban area problems. The three key areas of
interest were: (1) urban land use and dynamics of the residential and industrial
components (starting as early as in the 1950s), (2) mapping, analysis, and planning
of the urban transportation infrastructure (late 1950s), and (3) mapping density and
quality, of housing units, including environmental health conditions (starting as
early as 1960s).
Geographical areas of interest during the 1950-1970 period varied considerably.
Within the United States, Los Angeles and Phoenix appear to have been studied
more often than other cities, with the objective of determining pollution levels and
interest in “civilian”
urban remote sensing
applications began to
develop in the 1930s
