CHENNAI: Under Vehicle Screening/Scanning System (UVSS), which is used to scan and record images of the under-carriage and detect explosives, foreign objects and attached packages, has been commissioned at the vehicle entrance of Chennai Egmore railway station recently. It is being used on a trial basis.
Specifically designed to be used at sensitive locations like airports and railway stations, the UVSS has three high resolution cameras attached on the floor at the entrance, a side camera to capture the face of the driver and a front end camera to record the number plate of the vehicle.Railway Protection Force (RPF) personnel stationed at a separate booth near the UVSS installation monitor the images on a computer screen.
Many passengers take trains to southern regions of India from the Egmore station on a daily basis. Approximately 1,000 vehicles waltz in and out of the station everyday. For the system to click clear images, the vehicles need to travel at 10 kmph at the zone, which currently is proving to be a hassle. “A speed-breaker will be installed just before the floor cameras for that,” said an RPF official.
When a four-wheeler crosses a sensor loop at the zone, the driver camera, mounted on a pole near the booth, is triggered and clicks 10-15 frames of the driver window of the vehicle. A metal halide lamp is fitted above the camera to enable lighting after sunset.
The cameras fitted on the road then capture the under-frame of the vehicle, with a flash assembly provided the necessary lighting. Known as a Line Scan Camera (LSC), the camera is a special device which only scans and captures an area equal to that of a slit. Once triggered, it starts scanning through the slit and captures anything that dashes over the slit. The slit images generated by continuous scanning are sent to a ‘line-grabber card’ in the computer that will join these images to give a high-quality precise image of the under-frame of the vehicle. “Normally, security persons can search the inside of a car and the dicky easily. But going under every car would be tedious. With UVSS, if a bomb or ticking device is fitted under the car, then it can be easily detected,” said an RPF official.
The third camera mounted in front of the incoming vehicle will capture the number-plate of the vehicle. The computer screen inside the booth will immediately get the auto-cropped image of the number plate, side frame of the driver and well-lit image of the under-body of the vehicle. Zoom, contrast, brightness and other regular features are available on the software for closer inspection of the images. According to RPF officials, the current assembly faces no hassles in operation during the peak hours, as the queue of vehicles enables their slow movement through the passage and therefore facilitates efficient working of the UVSS system. A similar system at the Chennai Central station is on the anvil, sources said.