Researchers from the Ramón Llull University (Spain) have created a system capable of geolocating some videos by comparing their images and audio with a worldwide multimedia database, for cases where textual metadata is not available or relevant.

In the future, this could help to find people who have gone missing after posting images on social networks, or even to recognize locations of terrorist executions by organizations such as ISIS.

All of the data obtained is merged together and grouped in clusters so that, using computer algorithms developed by the researchers, they can be compared with those of a large collection of recorded videos already geolocated around the world.

In their study, published in the journal Information Sciences, the team used almost 10,000 sequences as a reference from the MediaEval Placing task audiovisual database, a benchmarking assessment of algorithms for multimedia content to detect the most probable geographical coordinates.

This allows for locating 3% of videos within a ten-kilometer radius of their actual geographical location, and in 1% of cases it is accurate to one kilometer — four times more accurately than achieved previously, according to the researchers.

Another application for the system is to facilitate geographical browsing in video libraries such as YouTube. For example, the search for  “Manhattan” (the city) could be disambiguated from “The Manhattans” 70s band and the Woody Allen film “Manhattan,” the researchers suggest.

The researchers recognize that their method will require a much larger audiovisual database to apply it to the millions of videos on the Internet.

http://www.kurzweilai.net/new-algorithms-locate-where-a-video-was-shot-from-its-images-and-sounds