Nyan M N, Tay F E H, Seah K H W, Sitoh Y Y
Department of Mechanical Engineering, National University of Singapore, Singapore.
J Biomech. 2006;39(14):2647-56. doi: 10.1016/j.jbiomech.2005.08.014. Epub 2005 Oct 5.
This paper describes the classification of gait patterns among descending stairs, ascending stairs and level walking activities using accelerometers arranged in antero-posterior and vertical direction on the shoulder of a garment. Gait patterns in continuous accelerometer records were classified in two steps. In the first step, direct spatial correlation of discrete dyadic wavelet coefficients was applied to separate the segments of gait patterns in the continuous accelerometer record. Compared to the reference system, averaged absolute error 0.387 s for ascending stairs and 0.404 s for descending stairs were achieved. The overall sensitivity and specificity of ascending stairs were 98.79% and 99.52%, and those of descending stairs were 97.35% and 99.62%. In the second step, powers of wavelet coefficients of 2 s time duration from separated segments of vertical and antero-posterior acceleration signals were used as features in classification. Our results proved a reliable technique of measuring gait patterns during physical activity.
本文描述了如何利用布置在衣服肩部前后和垂直方向的加速度计，对下楼梯、上楼梯和平地行走活动中的步态模式进行分类。连续加速度计记录中的步态模式分类分两步进行。第一步，应用离散二进小波系数的直接空间相关性，将连续加速度计记录中的步态模式段分离出来。与参考系统相比，上楼梯的平均绝对误差为0.387秒，下楼梯的平均绝对误差为0.404秒。上楼梯的总体灵敏度和特异性分别为98.79%和99.52%，下楼梯的分别为97.35%和99.62%。第二步，将垂直和前后加速度信号分离段中持续2秒的小波系数功率用作分类特征。我们的结果证明了一种在身体活动期间测量步态模式的可靠技术。
