A multi-scale human action recognition method based on Laplacian pyramid depth motion images

Human action recognition is an active research area in computer vision. Aiming at the lack of spatial muti-scale information for human action recognition, we present a novel framework to recognize human actions from depth video sequences using multi-scale Laplacian pyramid depth motion images (LP-DMI). Each depth frame is projected onto three orthogonal Cartesian planes. Under three views, we generate depth motion images (DMI) and construct Laplacian pyramids as structured multi-scale feature maps which enhances multi-scale dynamic information of motions and reduces redundant static information in human bodies. We further extract the multi-granularity descriptor called LP-DMI-HOG to provide more discriminative features. Finally, we utilize extreme learning machine (ELM) for action classification. Through extensive experiments on the public MSRAction3D datasets, we prove that our method outperforms state-of-the-art benchmarks.