  Single modality action recognition on RGB or depth sequences has been
extensively explored recently. It is generally accepted that each of these two
modalities has different strengths and limitations for the task of action
recognition. Therefore, analysis of the RGB+D videos can help us to better
study the complementary properties of these two types of modalities and achieve
higher levels of performance. In this paper, we propose a new deep autoencoder
based shared-specific feature factorization network to separate input
multimodal signals into a hierarchy of components. Further, based on the
structure of the features, a structured sparsity learning machine is proposed
which utilizes mixed norms to apply regularization within components and group
selection between them for better classification performance. Our experimental
results show the effectiveness of our cross-modality feature analysis framework
by achieving state-of-the-art accuracy for action classification on five
challenging benchmark datasets.
