关键词: 轨迹数据, 距离度量, 旋转、缩放、平移（RST）不变性, 最优旋转矩阵

Abstract: The trajectory similarity measure that is invariant to Rotation, Scaling and Translation（RST） operations is crucial to applications such as precise sign language recognition, similar trajectory index etc. However, traditional similarity measures do not meet this requirements, especially the rotation invariant. This paper proposes an RST invariant measure. This method begins by filtering, normalizing and resampling the trajectory, which is followed by an optimal estimation of rotation matrix between any two trajectories. After that, the interference of uncertain rotation is reliably removed. The proposed method has time complexity of [ON] and applies to both 2D and 3D trajectories. Compared with invariants like curvature and torsion, this method is quite insensitive to noises.

Key words: trajectory data, distance measure, Rotation, Scaling and Translation（RST） invariant, optimal rotation matrix