Title :
Novel intelligent wavelet filtering of embolic signals from TCD ultrasound
Author :
Marvasti, Salman ; Gillies, Duncan ; Markus, Hugh S.
Author_Institution :
Dept. of Comput., Imperial Coll. London, UK
Abstract :
Transcranial Doppler ultrasound can be used to detect emboli in blood flow for predicting stroke. Embolic signals (ES) have characteristic transient chirps suitable for wavelet analysis. We have implemented and evaluated the first on-line intelligent wavelet filter to amplify embolic signals building on our previous work in detection. Our intelligent wavelet amplifier uses the matching filter properties of the Daubechies 8th order wavelet to amplify ES. Even the smallest ES is enhanced without affecting the signal due to the blood flow. We show an increase of over 2 db (on average) in ES strength and a significant improvement in detection accuracy.
Keywords :
biomedical ultrasonics; brain; filtering theory; haemodynamics; haemorheology; matched filters; medical signal detection; wavelet transforms; Daubechies 8th order wavelet; blood flow; embolic signals; intelligent wavelet amplifier; intelligent wavelet filtering; matching filter; online intelligent wavelet filter; stroke prediction; transcranial Doppler ultrasound; transient chirps; wavelet analysis; Atrial fibrillation; Blood flow; Cardiology; Filtering; Filters; Fourier transforms; Signal analysis; Signal detection; Time frequency analysis; Ultrasonic imaging;
Conference_Titel :
Signals, Systems and Computers, 2004. Conference Record of the Thirty-Eighth Asilomar Conference on
Print_ISBN :
0-7803-8622-1
DOI :
10.1109/ACSSC.2004.1399422
