心冲击图信号中呼吸成分的时频检测方法研究

根据心冲击图(BCG)信号中呼吸成分对心动周期成分具有调制作用的事实,提出一种适用于坐姿BCG监测系统的呼吸成分时频检测方法。该方法先采用变频复解调(VFCDM)算法对BCG信号进行解调,得到不同中心频率的解调输出,再通过时频分析手段估计各个频段的瞬时频率及其幅值信息,最后实现呼吸成分时域波形的重建。为了验证算法的可行性和准确性,应用小波分析方法进行定性对比实验,并同步采集鼻热敏呼吸信号进行定量统计。实验结果表明,本文所提方法可以从BCG信号中较为准确地检测呼吸率成分,为多生理参数的无感觉同步监测做了有益的尝试。

The research on time-frequency detection method of respiratory component in ballistocardiogram signal

Based on the fact that the respiratory component modulates the cardiac cycle component in the ballistocardiogram (BCG) signal, we propose a method that detects respiratory with time-frequency analysis for the sitting ballistocardiography system. Firstly, we demodulated the BCG signal by using the variable frequency complex demodulation (VFCDM) to obtain the output for different center frequency of interest. Then we calculated the instantaneous frequencies and the instantaneous amplitudes by the time-frequency representation. We reconstructed the time-domain waveform of respiratory at last. In order to verify the feasibility and accuracy of this method, we applied wavelet transform and nasal thermistor signal to compare qualitatively and quantitatively. The simulation results showed that the proposed method could detect the respiratory rate from BCG signal more accurately, which provided meaningful attempt for monitoring the multiple physiological parameters synchronously and unconsciously.