Content-based video retrieval: Three example systems from TRECVid

The growth in available online video material over the Internet is generally combined with user-assigned tags or content description, which is the mechanism by which we then access such video. However, user-assigned tags have limitations for retrieval and often we want access where the content of the video itself is directly matched against a user's query rather than against some manually assigned surrogate tag. Content-based video retrieval techniques are not yet scalable enough to allow interactive searching on Internet-scale, but the techniques are proving robust and effective for smaller collections. In this article, we show three exemplar systems which demonstrate the state of the art in interactive, content-based retrieval of video shots, and these three are just three of the more than 20 systems developed for the 2007 iteration of the annual TRECVid benchmarking activity. The contribution of our article is to show that retrieving from video using content-based methods is now viable, that it works, and that there are many systems which now do this, such as the three outlined herein. These systems, and others can provide effective search on hundreds of hours of video content and are samples of the kind of content-based search functionality we can expect to see on larger video archives when issues of scale are addressed. (c) 2008 Wiley Periodicals, Inc.