Person of Interest - the workings of Video Analytics

Up to now, we have discussed quite a few interesting applications and points on visual analytics. But we have received some feedback asking to explain how it works. So here goes!

The basis of visual analytics, a practice of using computers to identify things or people of interest without an operator or a person having to view the video, are mathematical algorithms that monitor, analyze and manage big volumes of video. This means that video inputs are digitally analyzed and transformed into data that help people take decisions. It can be real time to help alert to specific incidents that could happen, such as an illegal suspect fleeing the country, and so on, or they can be post-event, looking incidents that have already occurred, for example a bombing or a fire in a store.

VA can happen in the centre, for example a central monitoring station, at the "edge", built into cameras which is ideal to locate live happenings, or as a combination of both. The optimal place to locate post-event analytics is on a central server as it is possible to search a large amount of recorded video for events, however this requires network capacity and processing power. But the main point on VA is that it works on motion detection and pattern recognition.

Motion Detection is basically examining each pixel in a given frame to detect the slightest movement. Pattern Recognition, on the other hand, recognizes specific patterns within a frame. These patterns or objects can be programmed and i.e, should a change happen or an object go missing the software immediately recognizes and sounds an alert.

The most common used types of video analytics used is violation of perimeters and recognition of license plates. Not only can this be used in surveillance, but in retail segment market analysis, to measure the number of people that pass in a given time (footfall), gender counting, shelf space effectiveness, and so on.

A fun and different way to see a little bit of VA in action, is watching a series called Person of Interest. It's just a TV show... but is it really?

Sources:
http://www.mistralsolutions.com/hs-downloads/tech-briefs/aug09-article-1.html
http://www.addic7ed.com/serie/Person_of_Interest/2/22/God_Mode
http://alexandra135.deviantart.com/art/Person-of-Interest-349555095