Image Processing Reference
In-Depth Information
7.1
Introduction
The variety of remote sensing imaging systems and urban remote sensing applica-
tions is due in part to the reciprocal exchange of expertise between the domains of
information technology and an emergent interest in the structural complexity and
dynamics of urban environments. Remote sensing is a domain of interdisciplinary
studies encompassing a wide array of applications. Broader and increasingly inter-
disciplinary applications are driven by the evolving technological characteristics of
remote sensing systems, increased availability of remotely sensed imagery, and
advances in data processing and analysis techniques. These drivers have inspired
new thinking about the urban environment and provided the impetus for urban
remote sensing (URS).
In this chapter, we trace the evolution of URS applications as driven by techno-
logical developments of imaging instruments. The focus is on satellite systems that
have been most commonly used for urban analyses. Through a chronological over-
view of applications, the development of urban remote sensing is outlined from the
early days of aerial photography to recent advances in satellite imaging and image
processing technologies. Finally, the chapter concludes with a summary of key
trends in the joint evolution of remote sensing systems and urban remote sensing
applications.
7.2
Evolution of Remote Sensing Systems
Urban environments are characterized by complex and dynamic physical and socio-
economic attributes that vary continuously across space and time. The ability to
map, monitor, and analyze such attributes from remotely sensed imagery greatly
depends on the characteristics of the imaging instruments (see related discussions
in Chapters 4 and 5). Remote sensing instruments include photographic (film-based
cameras) and non-photographic sensor systems (radiometers, digital cameras, radar
systems, and electro-optical scanners).
Current operational remote sensing systems are designed for specific earth
observation missions, and thus have different operational principles and technical
characteristics. The focus in this chapter is on imaging systems mounted on earth
orbiting satellite platforms, designed to collect imagery of the earth surface at
regular time intervals. Airborne imaging systems
have been commonly used in the early years of URS
but their technical characteristics are not discussed
here. Jensen (
1996
) provides a more detailed review
of airborne imaging systems' characteristics. The
following major imaging satellites will be covered
in this chapter:
current operational
remote sensing systems
have different
operational principles
and technical
specifications
