VIREO-TNO @ TRECVID 2015: Multimedia Event Detection

This paper presents an overview and comparative analysis of our systems designed for the TRECVID 2015 [1] multimedia event detection (MED) task. We submitted 17 runs, of which 5 each for the zeroexample, 10-example and 100-example subtasks for the Pre-Specified (PS) event detection and 2 runs for the 10-example subtask for the Ad-Hoc (AH) event detection. We did not participate in the Interactive Run. This year we focus on three different parts of the MED task: 1) extending the size of our concept bank and combining it with improved dense trajectories; 2) exploring strategies for semantic query generation (SQG); and 3) combining our visual classifiers with audio and/or textual classifiers. Among our 17 submitted runs, the following runs achieved top performances: - VIREO MED15 MED15EvalFull PS 0Ex MED p-manualfused 1: zero-example system with manual SQG, fused with textual (OCR) and speech (ASR) information. - VIREO MED15 MED15EvalFull PS 10Ex MED p-ConceptBankIDTEK0OCR 1: 10-example system using our Concept-Bank feature fused with the improved dense trajectories and the 0Ex manual visual system and OCR. - VIREO MED15 MED15EvalFull PS 100Ex MED c-ConceptBankIDTJointProb 1: 100-example system using Concept-Bank feature fused with the improved dense trajectories, using the joint probability to create the score.