基于K-均距异常因子的步态信号异常检测

Outlier Detection Based on K-mean Distance Outlier Factor for Gait Signal

  • 摘要: 针对在提取步态特征时,步态信号的有效采样距离短、模式异常多、难以满足周期划分需求的问题,提出了一种基于K-均距异常因子的步态序列异常检测方法.首先,对步态信号进行自适应小波去噪,通过边缘权重因子提取边缘点划分子模式,然后以4个特征值构建四维特征空间和特征子空间来计算异常因子,最后以异常值均值为标准,以步态周期为单位,对步态序列进行筛选.经公开数据集和自采数据集实验,结果证明在步态信号中检测步态周期模式异常的准确性、合理性和有效性.

     

    Abstract: To solve the difficulties of feature extraction for acceleration signals, due to the limited number of sampling points and many outlier patterns of gait signals, which can't be used to divide the gait cycle, we propose a novel outlier detection algorithm based on K-mean distance outlier factor detection. We use a wavelet de-noising method to adaptively pretreat gait signals, and extract the edge point of the gait series according to the edge weight. This achieves a four-dimensional feature space and feature subspace by the use of the four eigenvalues of each sub-pattern. We then compute the K-mean distance outlier factor. Lastly, we screen the gait series with the mean outlier value, and test it using the unit of the gait cycle. The promising experimental results demonstrate that the proposed algorithm is accurate and reasonable on open access datasets as well as our built datasets, and efficiently detects outliers in gait series.

     

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