Walking motion analysis using 3D non-harmonic analysis

The spatiotemporal spectra of a video that contains a moving object form a plane in the three-dimensional (3D) frequency domain. This plane, which is referred to as the theoretical motion plane, reflects the velocity, which is calculated from the slope, of the moving objects. In the present paper, we propose a high-resolution frequency analysis method, referred to as 3D non-harmonic analysis (NHA), which is only weakly influenced by the analysis window. In addition, we estimate the motion vectors of objects in a video using the plane-clustering method, in conjunction with the least-squares method (LSM), for 3D NHA spatiotemporal spectra. In experiments, we verify the accuracy of 3D NHA and its usefulness for a sequence containing complex motions, such as cross-over motion, by comparison with 3D fast Fourier transform (FFT). The experimental results show that increasing the frequency resolution contributes to high-accuracy estimation of a motion plane.