Silhouette transformation based on walking speed for gait identification

We propose a method of gait silhouette transformation from one speed to another to cope with walking speed changes in gait identification. When a person changes his/her walking speed, dynamic features (e.g. stride and joint angle) are changed while static features (e.g. thigh and shin lengths) are unchanged. Based on the fact, firstly, static and dynamic features are separated from gait silhouettes by fitting a human model. Secondly, a factorization-based speed transformation model for the dynamic features is created using a training set for multiple persons on multiple speeds. This model can transform the dynamic features from a reference speed to another arbitrary speed. Finally, silhouettes are restored by combining the unchanged static features and the transformed dynamic features. Evaluation by gait identification using silhouette-based frequency-domain features shows the effectiveness of the proposed method.