Ultrasound Beamforming with Virtual Sources for Deep-Field Resolution
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Solution Overview
Problem
Conventional ultrasound imaging techniques suffer from image distortion at focal depths due to the diffraction of ultrasonic waves, particularly in synthetic aperture methods, which reduce resolution with increasing observation depth.
Innovation Solution
An ultrasound image processing method that calculates transmission and reception delays using two-dimensional virtual sources or ellipses to form multi-beams through synthetic focusing, minimizing image distortion by aligning delays with a propagation shape model centered on virtual sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional synthetic aperture method using spherical waves is used, then the method is simple to implement, but the resolution is greatly reduced at long distance because the beam width increases as the observation depth increases due to diffraction phenomenon
Solution Approach 1:
The patent changes the mathematical model parameters from spherical wave propagation to plane wave propagation. This parameter change in the propagation shape model allows the beam width to remain constant with increasing depth, preventing the resolution degradation that occurs in conventional spherical wave methods at long distances.
Solution Approach 2:
The patent introduces a new dimensional approach by using virtual sources arranged in a line parallel to the array rather than a single point source. This dimensional change from point source to line source creates plane wave propagation characteristics, which maintain constant beam width and resolution across different observation depths.
2Measurement precision
If focusing method is used to increase lateral resolution, then the resolution in lateral direction is improved, but image distortion occurs at focal depth due to diffraction of ultrasonic waves
Solution Approach 1:
The patent changes the propagation model parameter from spherical wave to plane wave, which fundamentally alters how the ultrasound beam propagates through the medium. This parameter change eliminates the diffraction-induced beam spreading that causes image distortion at focal depths, while still maintaining the ability to focus and achieve high lateral resolution.
3Ease of operation
If spherical wave propagation model is used in synthetic aperture method, then the calculation is straightforward, but the beam width increases as observation depth increases causing resolution reduction
Solution Approach 1:
The patent modifies the propagation model parameter from spherical wave to plane wave, which changes the mathematical relationship from inverse-square law attenuation to linear propagation. This parameter change maintains calculation simplicity while eliminating the beam width increase with depth, thereby preserving resolution across all observation distances.
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
Prevents image distortion at focal depths by enhancing resolution and maintaining clarity across different observation distances in ultrasound imaging.
Implementation Method 1
because of diffraction, the beam spreads as the ultrasound travels through the object, making it lower than the resolution in the axial direction
Data Source
AI summary
An ultrasound image processing method according to an embodiment of the present disclosure includes transmitting and receiving an ultrasound signal to and from an object through an array in which a plurality of apertures are arranged along one direction, calculating at least one of a transmission delay and a reception delay of the ultrasound signal, and forming a multi-beam through synthetic focusing by reflecting the calculated delay on the ultrasound signal received by the array, wherein the calculating of the delay is calculated through a propagation shape model in which the ultrasound signal transmitted or received through the array is centered on virtual sources parallel to the array.