Multiple Continuous Virtual Paths Based Cross-View Action Recognition

Abstract

In this paper, we propose a novel method for cross-view action recognition via multiple continuous virtual paths which connect the source view and the target view. Each point on one virtual path is a virtual view which is obtained by a linear transformation of an action descriptor. All the virtual views are concatenated into an infinite-dimensional feature to characterize continuous changes from the source to the target view. To utilize these infinite-dimensional features directly, we propose a virtual view kernel (VVK) to compute the similarity between two infinite-dimensional features, which can be readily used to construct any kernelized classifiers. In addition, a constraint term is introduced to fully utilize the information contained in the unlabeled samples which are easier to obtain from the target view. The rationality behind the constraint is that any action video belongs to only one class. To further explore complementary visual information, we utilize multiple continuous virtual paths. The original source and target views are projected to different auxiliary source and target views using the random projection technique. Then we fuse all the VVKs generated from all pairs of auxiliary views. Our method is verified on the IXMAS and MuHAVi datasets, and the experimental results demonstrate that our method achieves better performance than the state-of-the-art methods.