Unsupervised Mining of Multiple Audiovisually Consistent Clusters for Video Structure Analysis

We address the problem of detecting multiple audiovisual events related to the edit structure of a video by incorporating an unsupervised cluster analysis technique into a cluster selection method designed to measure coherence between audio and visual segments. First, mutual information measure is used to select audio-visually consistent clusters from two dendrograms representing hierarchical clustering results respectively for the audio and visual modalities. A cluster analysis technique is then applied to define events from the audio-visual (AV) clusters with segments co-occurring frequently. Candidate events are then characterized by groups of AV clusters from which models are built by automatically selecting positive and negative examples. Experiments on the standard Canal9 data set demonstrates that our method is capable of discovering multiple audiovisual events in a totally unsupervised manner.