In this paper, we address the exploitation of computervision techniques to develop multimedia services andautomatic monitoring systems related to the securityand the privacy in public areas. The research is part ofa two-year ltalian project called LAICA, intended toprovide advanced services for citizens and publicofficers. Citizens want fast and friendly web access topublic places, to see the environment in real-timewithout violating the privacy laws. Public officers andpolicy centres want a fast and reactive monitoringsystem, capable to automatically detect dangeroussituations, given the huge amount of cameras that cannot be monitored simultaneously by human operators.In this work, we describe the project and the definedmethodologies in multi-camera video mosaicing,people tracking and consistent labelling, and access toprocessed data with face obscuration.