Quantification of the Effect of Array Element Pitch on Imaging Performance.
Quantification of the Effect of Array Element Pitch on Imaging Performance.
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阵列元件间距对成像性能影响的量化。
DOI：
10.1109/tuffc.2018.2794627
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Wilcox PD
中科院分区：
文献类型：
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作者：
Wilcox PD
本文研究了周期性超声阵列中元件的节距与其成像性能的关系，特别强调了离散空间采样产生的成像伪影（栅瓣）。尽管阵列元件节距的经典奈奎斯特规则众所周知，但它们仅提供了在单一频率下从具有无限大孔径的阵列中消除栅瓣所需的限制条件。物理阵列的孔径有限，大多数应用都采用宽带脉冲。由于这些原因，栅瓣伪影总是以某种程度存在，因此，实际的阵列设计基于将栅瓣伪影抑制到适合给定应用的水平。在本文中，开发了一个理论框架，使周期性成像阵列的点扩散函数能够分解为主瓣和不同阶栅瓣的贡献之和，从而允许栅瓣伪影被明确量化。数值模拟用于分析一维线性阵列在远场（仅转向）和近场（仅聚焦）场景中的性能，并推导出设计指南。结果表明，一般来说，经典奈奎斯特规则过于保守，并且只要在成像算法中对光线角度实施某些限制，就可以增加阵列的间距而不会显着影响图像质量。实验示例说明了两种配置的阵列的实际应用。
This paper investigates how the pitch of elements in periodic ultrasonic arrays is related to their imaging performance, with particular emphasis on imaging artifacts (grating lobes) arising from discrete spatial sampling. Although the classical Nyquist rules for array element pitch are well known, they only provide the limiting condition needed to eliminate grating lobes from an array with an infinitely large aperture at a single frequency. Physical arrays have finite-sized apertures and most applications employ broadband pulses. For these reasons, grating lobe artifacts are always present at some level, and practical array design is, therefore, based on suppressing grating lobe artifacts to a level appropriate to a given application. In this paper, a theoretical framework is developed that enables the point spread function of a periodic imaging array to be decomposed into the sum of contributions from a main lobe and different orders of grating lobes, thus allowing grating lobe artifacts to be unambiguously quantified. Numerical simulations are used to analyze the performance of 1-D linear arrays in both far-field (steering only) and near-field (focusing only) scenarios, and design guidelines are deduced. It is shown that in general, the classical Nyquist rules are overly conservative and that the pitch of an array can be increased without significantly compromising image quality, provided that certain constraints on ray angles are implemented in the imaging algorithm. Experimental examples are shown that illustrate the practical application to arrays in two configurations.