TRECVid 2007 Experiments at Dublin City University

In this paper we describe our retrieval system and experiments performed for the automatic search task in TRECVid 2007. We submitted the following six automatic runs: • F A 1 DCU-TextOnly6 : Baseline run using only ASR/MT text features. • F A 1 DCU-ImgBaseline4 : Baseline visual expert only run, no ASR/MT used. Made use of query-time generation of retrieval expert coefficients for fusion. • F A 2 DCU-ImgOnlyEnt5 : Automatic generation of retrieval expert coefficients for fusion at index time. • F A 2 DCU-imgOnlyEntHigh3 : Combination of coefficient generation which combined the coefficients generated by the query-time approach, and the index-time approach, with greater weight given to the index-time coefficient. • F A 2 DCU-imgOnlyEntAuto2 : As above, except that greater weight is given to the query-time coefficient that was generated. • F A 2 DCU-autoMixed1 : Query-time expert coefficient generation that used both visual and text experts.