US 7,611,467 B2 · Method and apparatus for extracting an envelope curve of a spectrogram

Abstract

A method and apparatus for extracting an envelope curve of a spectrogram, for use in measurement of blood flow velocity by using spectral Doppler techniques, the method comprising steps of: processing RF ultrasound echo signals to obtain Doppler signals; performing spectral analysis on the Doppler signals, to obtain a corresponding power spectrum P(f); estimating a forward maximum frequency fmax+ and a backward maximum frequency fmax− for the Doppler signals at a predetermined moment, according to the power spectrum P(f) of the Doppler signals at the predetermined moment; determining a noise frequency range according to the two maximum frequencies, so as to estimate an average noise power E; and correcting the forward maximum frequency and the backward maximum frequency by using the average noise power E. With the method of the invention, influence from the SNR and bandwidth on the envelope curve may be reduced, so as to be useful for accurate computation of blood flow parameters.

Claims16

Dependent claims

A method for extracting an envelope curve of a spectrogram, for use in measurement of blood flow velocity by using spectral Doppler techniques, comprising steps of:

A. processing RF ultrasound echo signals to obtain Doppler signals;
B. performing spectral analysis on the Doppler signals, to obtain a power spectrum P(f) of the Doppler signals which varies over time;
C. estimating a forward maximum frequency fmax+ and a backward maximum frequency fmax− for the Doppler signals at a predetermined moment, according to the power spectrum P(f) of the Doppler signals at the predetermined moment;
D. determining a noise frequency range based on the estimated forward maximum frequency and the estimated backward maximum frequency, and estimating an average noise power E within the determined noise frequency range;
and
E. correcting the forward maximum frequency and the backward maximum frequency by using the average noise power E to obtain the corrected forward maximum frequency Fmax+ and the corrected backward maximum frequency Fmax−.

3 more elements

An apparatus for extracting an envelope curve of a spectrogram, for use in measurement of blood flow velocity by using spectral Doppler techniques, the apparatus comprising:

a processing unit configured to process RF ultrasound echo signals to obtain Doppler signals;
an analyzing unit configured to perform spectral analysis on the Doppler signals to obtain power spectrum P(f) of the Doppler signals which varies over time;
a frequency estimation unit configured to estimate a forward maximum frequency fmax+ and a backward maximum frequency fmax− for the Doppler signals at a predetermined moment according to the power spectrum P(f) of the Doppler signals at the predetermined moment;
a noise estimation unit configured to determine a noise frequency range based on the estimated forward maximum frequency and the estimated backward maximum frequency, and to estimate an average noise power E within the determined noise frequency range;
and
a correcting unit configured to correct the forward maximum frequency and the backward maximum frequency by using the average noise power E to obtain the corrected forward maximum frequency Fmax+ and the corrected backward maximum frequency Fmax−.

3 more elements

Dependencies are inferred from the claim text.

Method and apparatus for extracting an envelope curve of a spectrogram

Life of this patent

Method and apparatus for extracting an envelope curve of a spectrogram

Life of this patent

Abstract

Claims16