In current video surveillance systems, commercial pan/tilt/zoom (PTZ) cameras typically provide naive (or no) automatic scanning
functionality to move a camera across its complete viewable field. However, the lack of scene-specific information inherently
handicaps these scanning algorithms. We address this issue by automatically building an adaptive, focus-of-attention, scene-specific
model using standard PTZ camera hardware. The adaptive model is constructed by first detecting local human activity (i.e.,
any translating object with a specific temporal signature) at discrete locations across a PTZ camera’s entire viewable field.
The temporal signature of translating objects is extracted using motion history images (MHIs) and an original, efficient algorithm
based on an iterative candidacy-classification-reduction process to separate the target motion from noise. The target motion
at each location is then quantified and employed in the construction of a global activity map for the camera. We additionally
present four new camera scanning algorithms which exploit this activity map to maximize a PTZ camera’s opportunity of observing
human activity within the camera’s overall field of view. We expect that these efficient and effective algorithms are implementable
within current commercial camera systems.
Keywords Computer vision - Machine vision - Motion detection - Surveillance - Security - Camera scanning - Motion history images