Edinburgh Napier University

  This document describes work aimed at determining whether the detection, by
computer vision, of pedestrians waiting at signal-controlled road crossings could be
made sufficiently reliable and affordable, using currently available technology, so as
to be suitable for widespread use in traffic control systems.
The work starts by examining the need for pedestrian detection in traffic control
systems and then goes onto look at the specific problems of applying a vision system
to the detection task. The most important distinctive features of the pedestrian
detection task addressed in this work are:
• The operating conditions are an outdoor environment with no constraints on
factors such as variation in illumination, presence of shadows and the effects of
adverse weather.
• Pedestrians may be moving or static and are not limited to certain orientations or
to movement in a single direction.
• The number of pedestrians to be monitored is not restricted such that the vision
system must cope with the monitoring of multiple targets concurrently.
• The background scene is complex and so contains image features that tend to
distract a vision system from the successful detection of pedestrians.
• Pedestrian attire is unconstrained so detection must occur even when details of
pedestrian shape are hidden by items such as coats and hats.
• The camera's position is such that assumptions commonly used by vision systems
to avoid the effects of occlusion, perspective and viewpoint variation are not valid.
•The implementation cost of the system, in moderate volumes, must be realistic for
widespread installation.
A review of relevant prior art in computer vision with respect to the above demands is
presented. Thereafter techniques developed by the author to overcome these
difficulties are developed and evaluated over an extensive test set of image sequences
representative of the range of conditions found in the real world.
The work has resulted in the development of a vision system which has been shown to
attain a useful level of performance under a wide range of environmental and
transportation conditions. This was achieved, in real-time, using low-cost processing
and sensor components so demonstrating the viability of developing the results of this
work into a practical detector.