Adaptive Clutter Filter for Ultrasound Doppler Signal Processing
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Solution Overview
Problem
Current clutter filtering methods in ultrasound systems often fail to accurately remove clutter signals from Doppler signals, especially when the power level of the pure Doppler signal is close to that of the clutter signal, leading to incomplete removal of clutter and potential loss of low-frequency components necessary for accurate blood flow velocity detection.
Innovation Solution
The proposed solution involves setting the cutoff frequencies of clutter filters based on the power and mean frequency of the clutter signal, using a signal processing unit to analyze the Doppler signal characteristics and adjust the filtering accordingly, either by modulating the signal or changing the cutoff frequency to effectively separate clutter from pure Doppler signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high cutoff frequency is set for the clutter filter to remove clutter signals, then the clutter signal removal is improved, but low-frequency components of the pure Doppler signal are also cut off
Solution Approach 1:
The patent applies dynamics by making the cutoff frequency adjustable rather than fixed. The cutoff frequency is dynamically changed based on the power level of the Doppler signal, allowing the system to adapt between removing clutter effectively and preserving low-frequency Doppler components depending on signal conditions
Solution Approach 2:
The patent changes the parameter of cutoff frequency based on the power level of the Doppler signal. When the Doppler signal power is high, a higher cutoff frequency is used to remove clutter; when the power is low, a lower cutoff frequency is used to preserve the Doppler signal components
2Loss of information
If a low cutoff frequency is set for the clutter filter to preserve pure Doppler signal, then the low-frequency components are preserved, but the clutter signal removal effectiveness is reduced
Solution Approach 1:
The system dynamically adjusts the cutoff frequency based on real-time assessment of the Doppler signal power level, switching between conservative and aggressive filtering strategies as needed
Solution Approach 2:
The cutoff frequency parameter is changed according to the power level of the Doppler signal, optimizing the balance between clutter removal and signal preservation for each specific measurement condition
3Reliability
If modulation is performed when Doppler signal amplitude is high, then clutter signal removal is improved, but modulation cannot be performed when amplitude is low
Solution Approach 1:
The patent changes the operating parameter (cutoff frequency) based on the power level of the Doppler signal, enabling effective clutter filtering across both high and low amplitude conditions without requiring modulation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for more precise removal of clutter signals, enhancing the accuracy of blood flow velocity detection by preventing the loss of low-frequency components and improving the quality of Doppler images.
Implementation Method 1
The Doppler signal may be obtained by alternately transmitting and receiving ultrasound signals to and from a target object
Data Source
AI summary
Embodiments for filtering clutter signal from Doppler signal in an ultrasound system are disclosed. In one embodiment, a Doppler signal acquiring unit may transmit and receive ultrasound signals to and from a target object to acquire Doppler signal. A signal processing unit performs filtering upon the Doppler signal by using a first clutter filter having a first cutoff frequency and compute an input signal power to filtered input signal power rate (IFR) for the Doppler signal. The signal processing unit is further configured to be responsive to the IFR to modulate the Doppler signal and perform filtering upon the modulated Doppler signal by using the first clutter filter or to perform filtering the Doppler signal by using a second clutter filter having a second cutoff frequency.