A solution to determine the positions of
　　transportation vehicles without any optical markers
　　in an area under camera
　　surveillance was introduced. This solution was based
　　on a net of cameras on the ceiling of the vehicle
　　operational areas. A robust
　　background subtraction method was performed to detect
　　the contours of all moving objects in every camera
　　frame. These so called
　　foreground objects contours were fed into a particle
　　filter to estimate the position, orientation and
　　speed of the detected objects over a
　　certain number of frames. Based on the camera data
　　this so-called state estimation was performed for all
　　foreground objects like
　　humans, other moving obstacles and the vehicles. Due
　　to the fact that the vehicles can be totally covered
　　by their payload, they
　　cannot be detected by color or shape. Instead, the
　　vehicles were identified by comparing their movement
　　with the movement of all
　　detected foreground objects.