Intelligent security system spots aggressive behaviour

A computer program can analyse CCTV images and spot aggressive human behaviour nine times out of ten, researchers have claimed. The team believe the research is an important step forward in intelligent security systems that could raise an alarm without requiring constant human vigilance.

Image-processing experts Abdelhak Ouanane and Amina Serir of the Université des Sciences et de la Technologie Houari Boumediene in Algiers, Algeria, used a geometrical analysis of images to create a silhouette of a person on the screen. The system maps the movements of the person’s limbs and the team then correlates those movements with aggressive and passive behaviour so that the algorithm learns what particular changes in geometry are associated with aggression.

The program can automatically distinguish between hand clapping, waving and a punch being thrown, for example. The system can also discern whether a person is walking, jogging or running. The research team say the resulting algorithm has 90 per cent accuracy compared to other systems, the best of which is around 80 per cent accurate they say. On a standard data set the accuracy is as high as 98 per cent.

The team points out that the algorithm is robust and not susceptible to changes in lighting conditions and noise in the images. This allows it to work well in a variety of indoor and outdoor settings, such as streets, airports, sports stadiums, etc. Moreover, the simplification of the images to human silhouettes reduces the computational overhead significantly and allows the analysis to be carried out quickly without the need for a high-performance computer.