Human activity recognition using multi-features and multiple kernel learning

• Presenting 3D shape features based on spherical harmonics representation.
• Presenting 3D motion features of the distal limb segments using kinematic structure.
• Fusing multiple features using multi kernel learning for human action recognition.

This paper presents two sets of features, shape representation and kinematic structure, for human activity recognition using a sequence of RGB-D images. The shape features are extracted using the depth information in the frequency domain via spherical harmonics representation. The other features include the motion of the 3D joint positions (i.e. the end points of the distal limb segments) in the human body. Both sets of features are fused using the Multiple Kernel Learning (MKL) technique at the kernel level for human activity recognition. Our experiments on three publicly available datasets demonstrate that the proposed features are robust for human activity recognition and particularly when there are similarities among the actions.