Multi-Wave Doppler Velocity Meter Using Non-Linear Interaction
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Solution Overview
Problem
Current Doppler-based tracking methods face limitations in precision and complexity, particularly in measuring the velocity of moving objects, especially deep-lying blood vessels, due to insufficient spatial resolution and range-velocity product maximum, which restricts the measurement of fast blood flows and often results in a lower signal-to-noise ratio.
Innovation Solution
The method employs multiple sources of emitted waves, such as ultrasound, to calculate the Doppler frequency shift from the non-linear interaction with the object, allowing for the determination of velocity without the need for frequency demodulation and achieving higher spatial resolution by focusing waves to intersect at a small region of interest, enabling the detection of both speed and direction of motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional Doppler methods are used to measure velocity, then the measurement can be performed, but the precision is insufficient and the signal-to-noise ratio is lower
Solution Approach 1:
The invention divides the measurement process into two distinct stages: first generating a stationary interference pattern through multiple wave sources, then measuring the Doppler shift of this pattern. This segmentation allows the system to benefit from both the spatial resolution of interference patterns and the velocity measurement capability of Doppler effects, thereby improving both precision and signal-to-noise ratio simultaneously
Solution Approach 2:
The invention introduces an interference pattern as an intermediary between the wave sources and the velocity measurement. This intermediary pattern serves as a reference framework that enhances the measurability of velocity-induced frequency shifts, effectively improving the signal-to-noise ratio while maintaining measurement precision
2Measurement precision
If conventional Doppler systems are used, then velocity measurement is possible, but the spatial resolution is insufficient especially for deep-lying blood vessels
Solution Approach 1:
The invention creates a localized interference pattern at the specific measurement location using multiple focused wave sources. This local interference pattern provides high spatial resolution exactly where needed, enabling precise velocity measurements of deep-lying blood vessels without being constrained by the limited spatial resolution of conventional Doppler systems
Solution Approach 2:
The invention transitions from single-source to multi-source wave generation, adding spatial dimensionality to the measurement system. By arranging multiple sources to create an interference pattern, the system achieves enhanced spatial resolution in three-dimensional space, particularly improving the ability to resolve deep-lying structures
3Measurement precision
If conventional Doppler methods are used, then the system can operate, but the device complexity increases due to the need for frequency demodulation
Solution Approach 1:
The invention extracts and eliminates the frequency demodulation step from the measurement process. By directly measuring the Doppler shift of the interference pattern frequency rather than requiring demodulation of carrier waves, the system simplifies the device architecture while maintaining or improving velocity measurement accuracy
Solution Approach 2:
Instead of using high-frequency carrier waves and demodulating them to extract velocity information, the invention inverts the approach by using the interference pattern frequency itself as the measurement reference. This reversal eliminates the need for complex demodulation electronics while preserving measurement precision
4Speed
If conventional Doppler systems are used, then measurement is possible, but the range-velocity product maximum restricts the measurement of fast blood flows
Solution Approach 1:
The invention changes the fundamental measurement parameter from direct high-frequency Doppler shift to the Doppler shift of the interference pattern frequency. This parameter change allows the system to measure a broader range of velocities including fast blood flows, as the interference pattern frequency provides a more suitable reference for high-velocity measurements without encountering the range-velocity product limitation
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 enhances the accuracy and simplicity of velocity measurement, allowing for the detection of both slow and fast motions with improved spatial resolution and signal-to-noise ratio, overcoming the limitations of conventional Doppler systems.
Implementation Method 1
producing a non-linear interaction which generates a response wave having frequency components dependent on the motion of the object
Implementation Method 2
calculating a Doppler frequency shift of the response wave
Data Source
AI summary
A method and system for determining a velocity of a moving object such as a body or a stream. The object is irradiated in a non-collinear configuration with multiple ultrasound waves overlapping in a region-of-interest (ROI) of the object. An response wave, resulting from the non-linear interaction among the incident waves and the object, is detected and the frequency variations of the response wave are determined. Data representing a Doppler-shift of this frequency is further determined and processed to calculate the velocity of the moving object.