Non-Uniform Weighted Sparse Arrays for Ultrasound Grating Lobe Suppression
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Solution Overview
Problem
Current ultrasound imaging systems using sparse arrays face challenges in suppressing excessive grating lobes while maintaining image quality and reducing hardware complexity, particularly in non-uniform weighted periodic sparse arrays, which often result in degraded Signal-to-Noise Ratio (SNR) and increased system complexity.
Innovation Solution
A method for the optimal design of non-uniform weighted periodic sparse arrays is proposed, involving the setting of intervals and number of array elements for transmit and receive sparse arrays to eliminate common grating lobes, and the application of apodization functions to optimize the beam pattern, using techniques such as convolution and up-sampling of aperture functions to achieve effective suppression of excessive grating lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a periodic sparse array is used to reduce the number of channels, then hardware complexity is reduced, but excessive grating lobes are generated that degrade image quality
Solution Approach 1:
The patent applies apodization functions (weighting functions) to change the amplitude distribution parameters of array elements. By optimizing the weighting coefficients w(n) in the aperture function a(n) = w(n) * rect(n/P), the patent suppresses excessive grating lobes while maintaining the periodic sparse array structure, thus resolving the contradiction between reduced channel count and grating lobe suppression.
Solution Approach 2:
The patent converts the harmful effect of grating lobes into a design constraint that guides the optimization of apodization functions. By systematically analyzing grating lobe positions and designing weighting functions that minimize their impact, the patent transforms the grating lobe problem into an opportunity for optimized beamforming that achieves both hardware reduction and image quality maintenance.
2Object-generated harmful factors
If apodization functions are applied to suppress grating lobes, then image quality is improved, but system complexity increases
Solution Approach 1:
The patent optimizes apodization function parameters (weighting coefficients) to achieve effective grating lobe suppression with minimal computational overhead. By deriving closed-form expressions for optimal weights and implementing efficient convolution-based calculation methods, the patent reduces the computational complexity of applying apodization functions while maintaining their effectiveness.
3Measurement precision
If the number of array elements is increased to improve resolution, then image resolution is improved, but hardware complexity and cost increase
Solution Approach 1:
The patent segments the aperture into periodic intervals of length P, using only L elements within each interval. This segmentation approach allows the system to achieve resolution comparable to a fully sampled array with N elements while using only N/P sparse elements, thus reducing hardware complexity while maintaining measurement precision.
Solution Approach 2:
The patent designs the periodic sparse array structure and apodization functions to simultaneously achieve multiple objectives: reducing channel count, suppressing grating lobes, and maintaining lateral resolution. This multi-functional design allows a single sparse array configuration to perform what would otherwise require multiple separate systems.
Data Source
AI summary
Disclosed herein is a method for the optimal design of an apodization function used for non-uniform weighted periodic sparse arrays for an ultrasound imaging system. The method includes the steps of (a) setting the interval PT of a transmit sparse array and the number LT of array elements within the interval PT so that common grating lobes are not generated in the beam patterns of the transmit sparse array and a receive sparse array; (b) setting the interval PR of the receive sparse array and the number LR of array elements within the interval PR so that common grating lobes are not generated in the beam patterns of the transmit sparse array and the receive sparse array; (c) setting a transmit apodization function WT(n) configured to be applied to the beam pattern of the transmit sparse array; and (d) setting a receive apodization function WR(n) configured to be applied to the beam pattern of the receive sparse array.