Action recognition using vague division DMMs

This study presents a novel human action recognition method based on the sequences of depth maps, which provide additional body shape and motion information for action recognition. First, the authors divide each depth sequence into a number of sub‐sequences. All these sub‐sequences are of uniform length. By controlling vague boundary (VB), they construct a VB‐sequence which consists of an original sub‐sequence and its adjacent sequences. Then, each depth frame in a VB‐sequence is projected onto three orthogonal Cartesian planes, and the absolute value of the difference between two consecutive projected maps is accumulated to form a depth motion map (DMM) to describe the dynamic feature of a VB‐sequence. Finally, they concatenate the DMMs of all the VB‐sequences in one video sequence to describe an action. Collectively, they call them VB division of depth model. For classification, they apply robust probabilistic collaborative representation classification. The recognition results applied to the MSR Action Pairs, MSR Gesture 3D, MSR Action3D, and UTD‐MHAD datasets indicate superior performance of their method over most existing methods.