The proposed framework to compute Eigen Joints is demonstrated in Fig. 2. We employ 3D position differences of joints to characterize action information including posture feature, motion feature , and offset feature in each frame. We then concatenate the three features channels as ݂Nmm, According to different experimental settings in Section 5.1, two normalization schemes are introduced to obtain . In the end, PCA is applied to D to compute EigenJoints.
To characterize the static posture information of current frame, we compute pair-wise joints differences within
the current frame:
To represent the offset feature or the overall dynamics of the current frame-ܿ with respect to the initial frame, we calculate the pair-wise joints differences between frame and frame