Monitoring of public and private sites has increasingly become a very sensitive issue resulting in a patchwork of privacy laws varying from country to country -though all aimed at protecting the privacy of the citizen. It is important to remember, however, that monitoring and vi sual surveillance capabilities can also be employed to aid the citizen. The focus of current development is primarily aimed at public and cor porate safety applications including the monitoring of railway stations, airports, and inaccessible or dangerous environments. Future research effort, however, has already targeted citizen-oriented applications such as monitoring assistants for the aged and infirm, route-planning and congestion-avoidance tools, and a range of environment al monitoring applications. The latest generation of surveillance systems has eagerly adopted re cent technological developments to produce a fully digital pipeline of digital image acquisition, digital data transmission and digital record ing. The resultant surveillance products are highly-fiexihle, capahle of generating forensic-quality imagery, and ahle to exploit existing Internet and wide area network services to provide remote monitoring capability.

The latest generation of visual surveillance systems have adopted recent technological developments in acquisition and communications. These advances have not so much changed the nature of surveillance as extended its reach and reliability. Fundamentally, systems remain relatively unintelligent with human operators remaining central to the threat assessment and response planning procedures found in CCTV installations. Nonetheless, the availability of high-performance computing platforms will ensure that cycle-hungry intellectual property gestating in academic and industrial research programs will have a major impact on the next generation of products. Video-Based Surveillance Systems: Computer Vision and Distributed Processing, surveys works in progress in laboratories from around the world. The first part of the book present the most recent trends in the industrial world including real-time systems for monitoring of indoor and outdoor environments, society infrastructures such as subways and motorways, retail stores and aerial surveillance. Part Two explores current best practices in a chain of algorithms required to perform robust and accurate real-time tracking for motion detection involving rapid and frequent lighting changes, the establishment of accurate temporally consistent object trajectories particularly in crowded scenes, and the classification of object types. Part Three contains contributions which attempt to analyze events unfolding in a monitored scheme. The last part reviews distributed intelligent architectures which are likely to exploit three key recent technological developments in light-weight distributed computing methodologies, and intelligent sensors. Sucharchitectures, in which signal analysis is moving towards sensing devices, can exploit the reduced bandwidth requirements of transmitting knowledge rather than pixels. Video-Based Surveillance Systems: Computer Vision and Distributed Processing provides timely information for professionals working in the areas of surveillance, image processing, computer vision, digital signal processing and telecommunications.

With the vast development of Internet capacity and speed, as well as wide adop- tion of media technologies in people's daily life, a large amount of videos have been surging, and need to be efficiently processed or organized based on interest. The human visual perception system could, without difficulty, interpret and r- ognize thousands of events in videos, despite high level of video object clutters, different types of scene context, variability of motion scales, appearance changes, occlusions and object interactions. For a computer vision system, it has been be very challenging to achieve automatic video event understanding for decades. Broadly speaking, those challenges include robust detection of events under - tion clutters, event interpretation under complex scenes, multi-level semantic event inference, putting events in context and multiple cameras, event inference from object interactions, etc. In recent years, steady progress has been made towards better models for video event categorisation and recognition, e. g. , from modelling events with bag of spatial temporal features to discovering event context, from detecting events using a single camera to inferring events through a distributed camera network, and from low-level event feature extraction and description to high-level semantic event classification and recognition. Nowadays, text based video retrieval is widely used by commercial search engines. However, it is still very difficult to retrieve or categorise a specific video segment based on their content in a real multimedia system or in surveillance applications.