Ultrasonic Doppler Velocity Measurement Clutter Rejection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonography methods face challenges in accurately measuring blood flow velocity due to interference from clutter signals from surrounding tissues and operator movements, which can lead to errors in phase shift detection.
Innovation Solution
The proposed solution involves a subject information acquisition apparatus that uses a combination of differential processing and adaptive signal processing, including the CAPON method, to selectively extract desired signals while reducing unwanted clutter, thereby improving the accuracy of blood flow velocity calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pulse Doppler method is used to measure blood flow velocity, then movement information can be acquired, but clutter signals from surrounding tissues and vessels interfere with the weak reflected waves from blood cells, causing errors in phase shift detection
Solution Approach 1:
The patent applies a differential filter to extract and remove clutter signals from the received ultrasonic signals. By computing the difference between signals at different time points, the filter separates the stationary or slow-moving clutter components from the faster-moving blood flow signals, thereby extracting only the desired blood flow information while eliminating interfering clutter signals.
Solution Approach 2:
The patent employs adaptive signal processing that dynamically adjusts filter parameters based on the statistical characteristics of the received signals. The system continuously adapts to changing clutter conditions by updating the differential filter coefficients in real-time, allowing optimal separation of blood flow signals from clutter signals under varying physiological and operational conditions.
2Reliability
If an MTI filter is used to eliminate clutter signals, then some clutter can be reduced, but the filter fails to sufficiently eliminate certain types of clutter signals, especially when reflectors are fluctuating due to tissue beating or hand shaking
Solution Approach 1:
The patent implements an adaptive feedback mechanism where the system continuously monitors the statistical properties of the received signals and adjusts the differential filter parameters accordingly. By feeding back information about clutter characteristics and signal variance, the system dynamically optimizes filter performance to maintain high clutter rejection effectiveness across diverse and changing operational conditions.
Solution Approach 2:
The patent changes the parameters of the differential filter adaptively based on the observed signal characteristics. By adjusting filter order, time constants, and weighting factors according to the measured clutter variance and signal-to-clutter ratio, the system maintains optimal performance whether dealing with stationary clutter, periodic tissue motion, or random hand-shaking artifacts.
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 enables more accurate measurement of blood flow velocity even in the presence of strong clutter components and tissue movements, enhancing the precision of velocity calculations.
Implementation Method 1
transmits acoustic waves to a subject, receives reflected waves reflected from the subject
Implementation Method 2
the movement velocity is calculated by detecting a phase shift of a reflected waveform from the object
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
With unwanted reflected waves, an error might be produced in a movement velocity detection of a measurement object. There is provided a subject information acquisition apparatus including a plurality of transducers configured to transmit an acoustic wave pulse to a subject, receive reflected waves reflected from a plurality of positions in the subject, and convert the reflected waves respectively into time series received signals and a processing unit configured to acquire movement information of the object by using a plurality of the received signals output from the plurality of transducers are provided. The processing unit extracts a plurality of signals each representing a movement component by using the plurality of received signals, performs adaptive signal processing by using the plurality of signals each representing a movement component, and acquires the movement information of the object by using a plurality of output signals obtained by the adaptive signal processing.