Echo cardio graphic Signal Processing Using Wavelets

Various areas like image processing, data compression and time frequency spectral estimation where the Wavelet have been applied. This paper describes another application in the filed of echocardiographic signals from an ultrasound machine. There are two areas of signals from the ultrasound echos - the imaging and the Doppler signals from blood flow in the chambers. Wavelet functions are shown to characterize Ultrasound data in terms of oriented texture component better. It can decorrelate non-coherent speckle noise better in the frequency domain. To determine the velocities of blood particles, the Doppler shift signals, synchronously detected with the base Ultrasound frequency, and called the I and Q signals are obtained. Rather than using the present day technique of CFFT method, the use of Wavelet decomposition of the signals has been made, using standard orthogonal Mallet Wavelet series, for example. Due to the usefulness of the Wavelets in providing better time resolution, particularly adjacent to the opening and closing instants of heart valves, the spectrogram based on Wavelet coefficients was found to be able to give improved resolution of the profiles of the E & A waves as well as in the evaluation of the pressure half-time for assessment of stenosed heart valve’s area.