Noise reduction and aliasing compensation in a doppler mode image
First Claim
1. An ultrasound system, comprising:
- a transmission/reception unit operable to transmit/receive ultrasound signals in a pulse repetition frequency (PRF) to form an n number of Doppler signals;
a signal processing unit operable to compute a first mean frequency based on an nth Doppler signal and an (n−
1)th Doppler signal and a second mean frequency based on an nth Doppler signal and an (n−
k)th Doppler signal, respectively, wherein k is a positive integer equal to or greater than 2, the signal processing unit being further operable to check whether the first and second mean frequencies exist within predetermined frequency ranges associated with the PRF, respectively, to determine occurrence of aliasing in the Doppler signals and compensate for the aliasing of the Doppler signals to thereby produce Doppler signals with the aliasing compensated;
wherein the signal processing unit includes a quadrature demodulating unit operable to demodulate the Doppler signals into baseband signals consisting of an I signal of an in-phase component and a Q signal of a quadrature component, andwherein the signal processing unit is operable to compute the first and mean frequencies through following equations,
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Abstract
The present invention relates to an ultrasound system and a method of forming a Doppler mode image. The ultrasound system comprises a transmission/reception unit operable to transmit/receive ultrasound signals at a pulse repetition frequency (PRF) to form an n number of Doppler signals. The ultrasound system further comprises a signal processing unit. The signal processing unit computes a first mean frequency based on an nth Doppler signal and an (n−1)th Doppler signal and a second mean frequency based on an nth Doppler signal and an (n−k)th Doppler signal, wherein k is a positive integer equal to or greater than 2. The signal processing unit estimates a Doppler frequency and compensate for aliasing of the Doppler signal based on the first and second mean frequencies to produce Doppler signal with the aliasing compensated. An image processing unit operable to form a Doppler mode image based on the Doppler signals produced by the signal processing unit.
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Citations
18 Claims
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1. An ultrasound system, comprising:
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a transmission/reception unit operable to transmit/receive ultrasound signals in a pulse repetition frequency (PRF) to form an n number of Doppler signals; a signal processing unit operable to compute a first mean frequency based on an nth Doppler signal and an (n−
1)th Doppler signal and a second mean frequency based on an nth Doppler signal and an (n−
k)th Doppler signal, respectively, wherein k is a positive integer equal to or greater than 2, the signal processing unit being further operable to check whether the first and second mean frequencies exist within predetermined frequency ranges associated with the PRF, respectively, to determine occurrence of aliasing in the Doppler signals and compensate for the aliasing of the Doppler signals to thereby produce Doppler signals with the aliasing compensated;wherein the signal processing unit includes a quadrature demodulating unit operable to demodulate the Doppler signals into baseband signals consisting of an I signal of an in-phase component and a Q signal of a quadrature component, and wherein the signal processing unit is operable to compute the first and mean frequencies through following equations, - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of forming a Doppler mode image in an ultrasound system having a transmission/reception unit, a signal processing unit and an image processing unit, comprising:
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a) at the transmission/reception unit, transmitting/receiving ultrasound signals in a pulse repetition frequency (PRF) to form an n number of Doppler signals; b) at the signal processing unit, demodulating the Doppler signals into baseband signals consisting of I signal of an in-phase component and a Q signal of a quadrature component, and computing a first mean frequency based on an nth Doppler signal and an (n−
1)th Doppler signal and a second mean frequency based on an nth Doppler signal and an (n−
k)th Doppler signal outputted from the transmission/reception unit, respectively, wherein k is a positive integer equal to or greater than 2, wherein the first and mean frequencies are calculated through the following equations, - View Dependent Claims (12, 13, 14, 15, 16, 17, 18)
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Specification