An effective public safety sensor system for heavily-populated applications requires sophisticated and geographically-distributed
infrastructures, centralized supervision, and deployment of large-scale security and surveillance networks.
Artificial intelligence in sensor systems is a critical design to raise awareness levels, improve the performance of the
system and adapt to a changing scenario and environment. In this paper, a highly-distributed, fault-tolerant, and energy-efficient
Smart Sensing Surveillance System (S4) is presented to efficiently provide a 24/7 and all weather security
operation in crowded environments or restricted areas. Technically, the S4 consists of a number of distributed sensor
nodes integrated with specific passive sensors to rapidly collect, process, and disseminate heterogeneous sensor data
from near omni-directions. These distributed sensor nodes can cooperatively work to send immediate security
information when new objects appear. When the new objects are detected, the S4 will smartly select the available node
with a Pan- Tilt- Zoom- (PTZ) Electro-Optics EO/IR camera to track the objects and capture associated imagery. The S4
provides applicable advanced on-board digital image processing capabilities to detect and track the specific objects. The
imaging detection operations include unattended object detection, human feature and behavior detection, and
configurable alert triggers, etc. Other imaging processes can be updated to meet specific requirements and operations.
In the S4, all the sensor nodes are connected with a robust, reconfigurable, LPI/LPD (Low Probability of Intercept/ Low
Probability of Detect) wireless mesh network using Ultra-wide band (UWB) RF technology. This UWB RF technology
can provide an ad-hoc, secure mesh network and capability to relay network information, communicate and pass
situational awareness and messages. The Service Oriented Architecture of S4 enables remote applications to interact
with the S4 network and use the specific presentation methods. In addition, the S4 is compliant with Open Geospatial
Consortium - Sensor Web Enablement (OGC-SWE) standards to efficiently discover, access, use, and control
heterogeneous sensors and their metadata. These S4 capabilities and technologies have great potential for both military
and civilian applications, enabling highly effective security support tools for improving surveillance activities in densely
crowded environments. The S4 system is directly applicable to solutions for emergency response personnel, law
enforcement, and other homeland security missions, as well as in applications requiring the interoperation of sensor
networks with handheld or body-worn interface devices.