基于互Wigner-Ville分布的表面肌电信号瞬时频率估计

当一块肌肉完成持续的收缩时,所记录的表面肌电信号的分析是一个用于评价局部疲劳进行性的有用的工具.在肌肉静态收缩期间,表面肌电信号功率谱的平均频率和中值频率常被用作肌肉疲劳的指示器.为了评价周期性动态收缩期间的局部肌肉疲劳,针对肌肉动态收缩时表面肌电信号的特点,提出了基于互Wigner-Ville分布的瞬时频率检测方法.通过一个类似于表面肌电信号统计性质的模拟的随机过程,评价了这一算法的估计误差.理论和实验证明,瞬时频率可以在较低的信噪比下很好地适合跟踪由于肌肉疲劳引起的频谱变化.

Instantaneous Frequency Estimation of the Surface Myoelectric Signal Wigner-Ville Distribution Based Technique

The analysis of the surface myoelectric signal is a valuable and the signal is recorded while a muscle is performing a sustained contraction tool for assessing the progression of localized fatigue. Mean and median frequencies of an electromyogram power spectrum are often used as indicators of muscular fatigue during static contraction. To evaluate muscle fatigue during cyclic dynamic contraction, according to the features of surface myoelectric signal during dynamic contraction, an instantaneous frequency detection technique based on cross Wigner-Ville distribution is proposed. The estimation error of the algorithm by means of a simulated stochastic process with statistical properties similar to the those of surface myoelectric signal. The theoretical and experiment validates that the instantaneous frequency suites well to tracking spectral changes due to muscle fatigue with very low SNR.