14. The method according to claim 12 , characterized in that, said sliding trajectory features include trajectory lengths of words and an word key point sequence, wherein said word key point sequence is an ordered combination of key points on the sliding trajectory of the word.
14. The method according to claim 12 , characterized in that, said sliding trajectory features include trajectory lengths of words and an word key point sequence, wherein said word key point sequence is an ordered combination of key points on the sliding trajectory of the word. 15. The method according to claim 14 , characterized in that, said key points include starting and ending key points as well as ordinary key points of the trajectory, wherein said ordinary key points are inflection points on the trajectory.