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ITI-CERTH participation to TRECVID 2011

This paper provides an overview of the tasks submitted to TRECVID 2011 by ITI-CERTH. ITI-CERTH participated in the Known-item search (KIS) as well as in the Semantic Indexing (SIN) and the Event Detection in Internet Multimedia (MED) tasks. In the SIN task, techniques are developed, which combine motion information with existing well-performing descriptors such as SURF, Random Forests and Bag-of-Words for shot representation. In the MED task, the trained concept detectors of the SIN task are used to represent video sources with model vector sequences, then a dimensionality reduction method is used to derive a discriminant subspace for recognizing events, and, finally, SVM-based event classifiers are used to detect the underlying video events. The KIS search task is performed by employing VERGE, which is an interactive retrieval application combining retrieval functionalities in various modalities and exploiting implicit user feedback.