Database Reference
In-Depth Information
14
Person Monitoring with Bluetooth
Tracking
Mathias Versichele, Tijs Neutens, and Nico Van de Weghe
14.1 The Difficult Nature of Measuring Human Mobility
Human mobility on different spatial and temporal scales affects many processes
taking place in our world. Although few will disagree that the large increase
in human mobility during the twenty-first century has improved our general
quality of life, it is increasingly confronting us with some of its more negative
implications as well: congestion in and around densely populated areas by daily
commuter traffic and the resulting strain on our environment, safety issues
arising from the gathering of large crowds in relatively small areas, sudden risks
of global pandemics and the difficulty of containing them, and so on. As such, an
increase in human mobility should be accompanied by a deeper understanding
of the processes governing these movements in order to better mitigate their
negative implications.
A starting point in learning more about these movements is adequately mea-
suring them. Until recently, this has been quite problematic. Qualitative methods
such as shadowing and the collection of travel diaries are known to be error prone
and labor intensive. An alternative method of tracking people in smaller-scale
settings is through video surveillance systems. Despite technological advance-
ments in the last decade, using cameras to reconstruct the movements of a large
number of people in a realistic environment remains very difficult. Correctly
identifying trajectories of individuals in one camera view is already nontrivial
due to interactions between moving objects, changing illumination in outdoor
environments, and so on. Reconstructing trajectories over multiple camera views
is even more challenging and to date remains somewhat of a scientific fiction.
A third way of measuring human movement is through the use of proxies:
objects whose movements are in some way linked to the movement of humans
and can thereby serve as indicators of these movements. A rather unusual exam-
ple of this is the tracking of one-dollar bills throughout the United States (as
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