Vi stands for Video Intelligence. These are advanced security Camera's with capability to generate or trigger alerts. These alerts can be then sent to a laptop or smart phone of a security officer who can initiate the action to avert a major crisis.
So in a sense Vi is used in Disaster Aversion. The Camera's have various capabilities like to find if a Baggage lies unclaimed or more than a prerequisite number of people enter a restricted area. These Camera's are Motion or Thermal Camera's and the latter can work even during the night.
Vi is a important security devices in countries like India which are dealing with Terror Attack aftermath and require proactive security with lack of trained staff and sniffer dogs. Also population explosion creates more problems in manual checking.
Advances in the technology i n future may make even baggage checking automated.
Some links that may help
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