Wavelet analysis of quadrature Doppler ultrasound signals

Author

Aydin, N. ; Markus, H.S.

Author_Institution

St. George´´s Hosp. Med. Sch., London, UK

fYear

2000

fDate

2000

Firstpage

251

Lastpage

256

Abstract

Most Doppler ultrasound systems employ quadrature demodulation techniques at the detection stage. The information concerning flow direction encoded in the phase relationship between in-phase and quadrature-phase channels is not obvious at this stage. Complex FFT can be used to obtain directional information in the frequency domain as well as time-frequency analysis of Doppler signals. However it has an inherent time-frequency resolution limitation. The wavelet transform allows the time-frequency resolution compromise to be optimized. Mapping directional information in scale domain is also desirable. A method based on the utilisation of complex wavelets and negative scales is described. It eliminates the intermediate processing stages for obtaining directional Doppler signals for time-scale analysis

Keywords

biomedical ultrasonics; demodulation; medical signal processing; time-frequency analysis; wavelet transforms; FFT; flow direction; frequency domain; negative scales; phase relationship; quadrature Doppler ultrasound signals; quadrature demodulation; quadrature-phase channels; time-frequency analysis; time-frequency resolution limitation; time-scale analysis; wavelet analysis; wavelet transform;

fLanguage

English

Publisher

iet

Conference_Titel

Advances in Medical Signal and Information Processing, 2000. First International Conference on (IEE Conf. Publ. No. 476)

Conference_Location

Bristol

ISSN

0537-9989

Print_ISBN

0-85296-728-4

Type

conf

DOI

10.1049/cp:20000346

Filename

889980