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Backlight analysis

Behaviour analysis by video motion detection in highly noised light conditions (Glare)  One of the most difficult situations when installing a video protection application based on intelligent video motion detection is the effect of public lighting and car lights from the public side. It is very common that a sensitive site is close to a public area, with a road open to public traffic, and that the site fence on this side should be protected by intelligent video surveillance too. When cameras are mounted parallel to fence in order to check it on the length side, we are also exposed to traffic light as well as image partial or total saturation (glaring). Hopefully, EVITECH proposes a solution in order to analyse events despite the halo of cars.

In the XVision project, form the competitivity group SYSTEM@TIC, supported by CG92, we study techniques for video motion detection even in backlight, or through the car light halos. This project will be an occasion to develop and experiment a new sensor, invented by Professor Ni (from NIT) for backlight image acquisition, and to test various video motion detection algorithms for detecting in this kind of situations. Until the disposal of this sensor, we have developed a first set of video motion analysis algorithms for market CCD and CMOS sensors, for the particularly sensitive case where a mobile object (a car, a truck, ...), has its lights turned toward the camera, without completly glaring it, with a halo making detection almost impossible. These algorithms will be more efficient with the XVision sensor, since it will resist to glare.

One can see, on the right of this page, an example of halo detection (the blue square) with an ordinary video motion detection software. The vehicle is detected with its halo, as well as lighting effects that it provokes (the grey car on the left image side).

When a target (e. g. a walking person) leaves the car and gets close to the fence, the corresponding target is integrated in the halo and the possible intrusion cannot be analysed.

This situation is really difficult for site security, since after such an analysis, there are only two solutions : (1) raise an alarm (but this will raise lots of false alarms each time a car runs or stops on the site side), or (2) not raise an alarm and wait until the fence is clear for proper detection (but this is a security hole).

In order to propose a satisfying behaviour in these situations, EVITECH has developed a video motion detection system based on differential analysis of components, which applies like a superposition of layers on a building map.

Over the lowest layer, with the quiet night on the street, is superposed the public light layer, and then the car and its lights, the light reflections on the side, and finally the intruder, whose behaviour and target can be analysed (here, a target of the "Person" type is detected, and named "P-5"). Thus even when the target is fully integrated to the car lights halo, like on the left picture, our Jaguar intelligent video motion detection software detects and recognizes the intruder moves.

For illustrating the car position, a display of a traversing layer is used, especially on the car lights, since no video motion detection will be possible on the glared areas.

This technological evolution is very important, for security of interfaces with public domains, since the automatic surveillance of sensitive sites sides by video motion detection must be ensured even when cameras are installed over the fence line, along an open road. "One outstanding point in this technology," declares Laurent Assouly, Marketing Director, "is the capacity to detect and recognize targets of very low visibility against the halo, and this as close as it is possible to the car lights. It is a real progress in comparison with current technology art in video motion detection. At EVITECH, we permanently work for improving functional possibilites of our video motion detection solutions, and to bring the maximum level of comfort and reliability to our customers."