City Surveillance needs can be quite varied. There will be groups that are responsible for protecting building assets. Graffiti and Vandalism detection can be an important application for them. Traditional motion detection systems can detect graffiti but they would also detect all the many passersby on the street. A non-motion detection algorithm based system is required (IQ 140) to detect the graffiti while ignoring innocent people who are just walking past. In one European city they had a very severe graffiti problem. Each time the buildings were repainted the graffiti artists struck again. Repainting buildings can be very expensive and hence the city council had to find a solution. They put in an IQ 140 level Graffiti detection system mounted on a van. Using infrared cameras the system was able to catch the culprits on the first day after it was installed. The news spread very quickly among graffiti artists and the problem disappeared overnight – at least in their neighbourhood.

Other groups will require the city surveillance system to monitor traffic. Often there are special slow speed zones near schools or beside shopping malls and hospitals Monitoring such locations has traditionally been very expensive because the detection of speed and the recognition of vehicles previously required significant civil works such as the digging of roads for the laying of magnetic loops as well as very expensive cameras. With modern systems where the video analysis system can do everything (triggering of the event, detection and recognition) the economics have changed and these systems can be widely implemented at a tenth of the cost of the traditional systems.

The most important focus of city surveillance systems however is on the people themselves. The objective is to keep people safe and prevent accidents or criminal activities. Not all activities are easy to detect. As has been discussed it is very difficult to detect if two people are fighting as this can take many different forms.

However many associated behaviours can be detected. For instance, if a person falls down as a result of a fight, this can be detected. If a person begins to run suddenly – this too can be detected. If crowds gather suddenly this could be a symptom of some unusual activity as well. Having a system that can monitor various types of human behaviour can help the city's officials ensure the safety of their citizens.