Transport

Machine vision has application in many aspects of transport. For example, it can be used to collect and understand data useful in transport planning and safety. It can also play an active role in navigation and vehicle guidance.

Traffic Monitoring

Monitoring traffic is a vital part of transport planning. Human observers are currently used, but this approach is time consuming and the data captured limited. An automated system to study traffic movements is being developed which aims to identify vehicles entering an area under observation, and monitor their movements and manoeuvres. Using images from a single camera, vehicles can, thereby, be located precisely and tracked as it moves in the scene. To obtain information on the actual position of the vehicles, the system is given a model of the scene and the exact position of the camera. Using this geometrical knowledge, a full understanding of vehicle movements can be obtained for subsequent analysis.

Aerial Navigation

At present, the navigation of airborne vehicles relies on the use of active remote sensing equipment. These techniques are very expensive and an automated system to interpret aerial images, using passive image sensing, combined with machine vision techniques, is being developed. The system operates by identifying road networks in the scene below (Fig 1), and matching them with stored maps of the roads in the area (Fig 2). The roads are identified by processing the image with computational filters that pick out road-like features (Fig 3). Further processing modifies the roads into a series of straight line segments. The characteristics and relationships between these segments can be compared with the stored map which has been similarly processed (Fig 4). This system can work over a range of altitudes and has potential use in the autonomous guidance of aircraft.

Transport Safety

Video monitoring by human operators is applied widely to transport safety. This activity is labour intensive, and operators are prone to fatigue. Machine vision, however, is now capable of providing valuable assistance by drawing attention to predefined events of interest. Systems using neural nets possess the flexibility to ignore acceptable events, but to generate an alarm in unacceptable situations. To do this, the neural net must be trained to accept the normal range of lighting and visibility likely in an outdoor situation. Events such as intruders, or obstructions in the scene, can then be identified by the system. To make the system more robust, training continues whilst it is in place. This allows it to adapt to slowly changing situations, while retaining its sensitivity to unacceptable occurrences.