Bloodflow velocimetry using wideband signals and wavelet transforms

This paper describes bloodflow velocimetry using wavelet transforms and wideband signals. Acoustic signals with high fractional bandwidths and/or large time-bandwidth products are processed with wideband/wavelet techniques, thereby removing many of the narrowband assumptions typically invoked. The received signals are assumed to be reflected from particles moving in the blood stream. Instead of measuring the Doppler shift associated with the reflection, and time-scaling of the signal is obtained. This time-scaling more accurately reflects the effects of motion on the signals than does a Doppler shift since a Doppler shift is an approximation to time-scaling. The continuous wavelet transform processing is then used to obtain the axial velocity of scatterers.