小波尺度图分析法及其在超声血流多普勒信号中的应用

Analysis of Wavelet Scalogram of Blood Flow Ultrasonic Doppler Signal.

将现代小波尺度图分析方法应用到人体血流多普勒信号的谱估计之中 ,计算血流多普勒信号的功率谱 ,得到小波意义上的尺度图。方法从时频分布的观点 ,小波尺度图是一种仿射平滑的Wign er Ville分布 ,具有恒“Q”特性的时间频率分析窗 ,对于人体颈总动脉的仿真多普勒血流信号 ,进行了小波尺度图的研究。结果通过血流多普勒信号的小波尺度图研究 ,发现利用小波尺度图可以提高血流多普勒信号低频段的频谱分辨率。结论利用小波方法估计人体血流多普勒信号的频谱特性是可行的 ,估计结果的低频段频谱的分辨率较高 ,从而可以提高小血管中低速血流的估计精度。

Objective To study the power spectrum density of blood flow ultrasonic Doppler signal using wavelet analysis. Method Doppler signal of blood flow in human common carotid artery was studied with wavelet scalogram analysis, an affine smoothing Wigner Ville transform with a constant “Q' character. Result Wavelet scalogram of blood flow ultrasonic signal had a higher distinguishability than STFT spectrogram in the low frequency portion, but had poorer decussation terms than spectrogram. Conclusion It is practicable to estimate the spectrum of Doppler signals of blood flow by the wavelet analysis method. And this can be used in low speed blood flow for higher resolution of spectrum in the low frequency portion.