High discrimination of nuisance alarms in a low cost movement videosensing system for remote surveillance of unattended sites

The on-going improvement of the digital image processing technologies together with the usage of specialised hardware has lead to the development of the system we are now introducing. The system incorporates a videosensor with improved capabilities on nuisance alarm discrimination based on an algorithm which combines both movement detection and object tracking with the aim of providing a wide range of criteria to program and select alarm situations. A TMS320C44 digital signal processor from Texas Instruments Inc. carries out the videosensing algorithm, being able to process up to four different and simultaneous video sources (CCTV cameras). The algorithm allows the usage of both local and global parameters to be applied to particular image areas or to the whole video frame. This set of parameters include: maximum speed of the moving objects; localisation of the areas of interest (alarm zones); order of intersection of the moving objects with the alarm zones or the size of the objects along their trajectories. The other basic component of the system is based on a video codec (IIT VCP) which uses the H.263 ITU-T standard on real time video coding. The high compression rates which the H.263 accomplishes allows the transmission of real time video through low bandwidth data links (28800 to 64000 bps) and the utilisation of the IP protocol makes it feasible to integrate our system in practically any data network with a minimal investment in communication equipment.