To operate successfully, the established biometric such as face, fingerprint usually require proximal sensing or physical contact. However, the gait the only one biometric that can be easily perceived at a distance. 人脸、指纹等生物特征通常要求近距离或者接触性的感知,在远距离情况下无法使用,而步态是此情况下唯一可感知的生物特征。