也可以把这种坐标，看成是空间中的极坐标，它其实使用了，距离原点的距离，然后用角度这种标尺，来确定了方向。

So, in a way, you can think of these as a space analog of polar coordinates because you just use distance to the origin, and then you have to use angles to determine in which direction you're going.

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通过大量试验表明，该系统可在线进行动作人的典型行为识别，对目标尺度变化，小角度倾斜和旋转具有一定程度的鲁棒性。

The results through extensive experiment show that the system can make on-line typical action recognition, and is robust to the object's size change, certain incline degree and revolve.

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