Method and system for automatic measurements of doppler waveforms
First Claim
1. A method of processing Doppler data comprising steps of:
- forming a plurality of first Doppler signals in response to receiving energy from an object of interest, said received energy having a range of frequency components, each first Doppler signal being indicative of intensities of frequency components;
forming a second Doppler signal from said first Doppler signals such that said second Doppler signal is indicative of values of a time-varying parameter of interest, said second Doppler signal having a succession of first peaks; and
determining a noise component within said second Doppler signal, including limiting implementation of said determination to time periods corresponding to regions between said first peaks of said second Doppler signal and including basing said determination upon first portions of said first Doppler signals independent of second portions upon which said values of said time-varying parameter are based.
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Accused Products
Abstract
A method and system of processing Doppler data includes determining a noise component independently of automatic signal analysis. A succession of frequency spectra is formed in response to receiving reflected energy from an object of interest. A Doppler waveform is then derived from the succession of frequency spectra. The execution of noise estimation is limited to time periods between peaks of the Doppler waveform, providing a first level of isolation from the true-signal processing. Implementation of the noise estimation is based upon portions of the frequency spectra that are independent of the portions from which the Doppler waveform is derived. This provides a second level of isolation. The determined noise component is used as a threshold level in subsequent derivation of the Doppler waveform. Preferably, there are multiple noise thresholds that are adaptively utilized to permit application of a short search block during Doppler frequency detection.
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Citations
19 Claims
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1. A method of processing Doppler data comprising steps of:
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forming a plurality of first Doppler signals in response to receiving energy from an object of interest, said received energy having a range of frequency components, each first Doppler signal being indicative of intensities of frequency components; forming a second Doppler signal from said first Doppler signals such that said second Doppler signal is indicative of values of a time-varying parameter of interest, said second Doppler signal having a succession of first peaks; and determining a noise component within said second Doppler signal, including limiting implementation of said determination to time periods corresponding to regions between said first peaks of said second Doppler signal and including basing said determination upon first portions of said first Doppler signals independent of second portions upon which said values of said time-varying parameter are based. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of processing Doppler data for medical applications comprising steps of:
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forming a series of frequency spectra in response to receiving ultrasonic reflections from an object of interest, each frequency spectrum being a sequence of bins; determining a first noise threshold indicative of a background noise component of said frequency spectra; and forming a maximum Doppler frequency waveform based upon said frequency spectra, including searching each frequency spectrum for a maximum frequency utilizing a search block of first and second groups of a small number of bins and including utilizing said noise threshold for each application of said search block, wherein utilizing said noise threshold includes determining whether successive bins of said first group each have an intensity value exceeding said noise threshold and, if so, whether a maximum intensity value of successive bins of said second group exceeds a sum of a function of said noise threshold and a calculated intensity value within a range of said intensity values of said first group. - View Dependent Claims (12, 13, 14, 15)
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16. A system for providing automatic Doppler data processing for medical applications comprising:
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an ultrasound transducer; spectra means for generating a series of frequency spectra in response to receiving ultrasound energy at said transducer, said spectra means having a first output of said frequency spectra, each frequency spectrum being indicative of intensities of frequency components of said received ultrasound energy; waveform means connected to said first output for generating a Doppler waveform of values of a time-varying parameter of interest in response to said frequency spectra, said waveform means having a second output in which said Doppler waveform has a succession of first peaks; and noise estimator means connected to said second output for determining a noise level during periods between successive first peaks based upon first portions of said frequency spectra remote from second portions upon which said values of said Doppler waveform are based. - View Dependent Claims (17, 18, 19)
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Specification