Title :
Multifrequency Doppler: improving the quality of spectral estimation by making full use of the information present in the backscattered RF echoes
Author :
Loupas, Thanasis ; Gill, Robert W.
Author_Institution :
Div. of Radiophys., CSIRO, Chatswood, NSW, Australia
fDate :
7/1/1994 12:00:00 AM
Abstract :
This paper investigates the application of the two-dimensional Fourier transform in the context of pulsed wave Doppler. It is shown that two-dimensional spectral analysis of the backscattered RF echoes provides individual Doppler spectra corresponding to the whole range of transmitted frequencies which can be combined, after proper scaling, to form a "multifrequency" spectral estimate. Theoretical expressions are derived for the signal-to-noise ratio of the multifrequency sonogram which predict substantial gains over the conventional (one-dimensional) approach for Doppler processing. These predictions are verified by means of extensive simulations, which also provide an insight into the effect of electronic noise.<>
Keywords :
Doppler effect; backscatter; biomedical ultrasonics; medical signal processing; patient diagnosis; spectral analysis; 2D Fourier transform; 2D spectral analysis; Doppler processing; backscattered RF echoes; cardiovascular disease diagnosis; electronic noise; individual Doppler spectra; multifrequency Doppler; multifrequency sonogram; multifrequency spectral estimate; proper scaling; pulsed wave Doppler; pulsed wave Doppler ultrasound; signal-to-noise ratio; simulations; spectral estimation; transmitted frequencies; Demodulation; Discrete Fourier transforms; Fluctuations; Fourier transforms; Frequency estimation; Radio frequency; Signal to noise ratio; Smoothing methods; Sonogram; Spectral analysis;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on