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(11) | EP 0 396 432 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Monitoring apparatus |
| (57) Monitoring apparatus for monitoring traffic flow in a tunnel is disclosed comprising
a plurality of cameras 10, 12, 14 each connected to a camera controller 60, 62, 64.
Each camera controller includes an image memory for periodically storing still images
from the camera associated therewith. A plurality of incident detectors 40 - 45; 46
- 51 are associated with each camera 10, 12, and lie within the field of view of that
camera. The incident detectors detect the passage of vehicles in a carriageway of
the tunnel and determine whether or not a traffic incident eg congestion or an accident
has occurred in accordance with an algorithm. When an incident has occurred an incident
detection signal is generated which is communicated to the camera controllers via
a central controller 66. The image memory of the relevant camera controller is responsive
to the detection signal to identify and freeze a plurality of images prior to the
incident which are then passed to the central controller, so that the circumstances
leading up to the incident can be reviewed. |