A Spatio-Temporal Descriptor for Dynamic 3D Facial Expression Retrieval and Recognition

Abstract

The recent availability of dynamic 3D facial scans has spawned research activity in recognition based on such data. However, the problem of facial expression retrieval based on dynamic 3D facial data has hardly been addressed and is the subject of this paper. A novel descriptor is created, capturing the spatio-temporal deformation of the 3D facial mesh sequence. Experiments have been implemented using the standard BU - 4DFE dataset. The obtained retrieval results exceed the state-of-the-art results and the new descriptor is much more frugal in terms of space requirements. Furthermore, a methodology which exploits the retrieval results, in order to achieve unsupervised dynamic 3D facial expression recognition is presented, in order to directly compare the proposed descriptor against the wealth of works in recognition. The aforementioned unsupervised methodology outperforms the supervised dynamic 3D facial expression recognition state-of-the-art techniques in terms of classification accuracy.