Source Density Apodization: Image Artifact Suppression Through Source Pitch Nonuniformity.
Source Density Apodization: Image Artifact Suppression Through Source Pitch Nonuniformity.
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源密度变迹：通过源间距不均匀性抑制图像伪影。
DOI：
10.1109/tuffc.2019.2945636
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Alles EJ
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文献类型：
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作者：
Alles EJ
传统的超声成像探头通常包括有限尺寸的周期性间隔换能器元件阵列，在相控阵的情况下，可能导致严重的光栅和副瓣伪影。虽然侧瓣可以通过振幅apodization（“AmpA”）有效地抑制，但由于换能器放置的周期性而产生的光栅瓣只能通过降低元件间距来抑制，这在技术上具有挑战性且成本高昂。在这项工作中，我们提出了源密度apodiization（“SDA”）作为替代apodiization方案，其中空间源密度（因此，元件间距）在成像孔径中变化。利用能够视频速率二维成像以及源阵列几何结构动态和任意重构的全光超声成像装置，我们在数值和实验上展示了SDA和AmpA在大量源中是如何等效的。对于低数量的源，SDA显示出优越的图像质量，因为两侧和光栅瓣被有效地抑制。此外，我们还演示了如何使用非对称SDA方案来局部和动态地提高图像质量。最后，我们演示了非平滑变化的空间源密度（例如随机阵列或存在源定位不确定性或不准确的情况下获得的密度）如何产生严重的图像伪影。因此，即使在低通道数的情况下，SDA的应用也可以产生高图像质量，这最终可以使用降低复杂性的采集系统获得更高的成像帧率。
Conventional ultrasound imaging probes typically comprise finite-sized arrays of periodically spaced transducer elements which, in the case of phased arrays, can result in severe grating and sidelobe artifacts. Whereas side lobes can be effectively suppressed through amplitude apodization (“AmpA”), grating lobes arising from periodicity in transducer placement can only be suppressed by decreasing the element pitch, which is technologically challenging and costly. In this work, we present source density apodization (“SDA”) as an alternative apodization scheme, where the spatial source density (and, hence, the element pitch) is varied across the imaging aperture. Using an all-optical ultrasound imaging setup capable of video-rate 2-D imaging as well as dynamic and arbitrary reconfiguration of the source array geometry, we show both numerically and experimentally how SDA and AmpA are equivalent for large numbers of sources. For low numbers of sources, SDA is shown to yield superior image quality as both side and grating lobes are effectively suppressed. In addition, we demonstrate how asymmetric SDA schemes can be used to locally and dynamically improve the image quality. Finally, we demonstrate how a nonsmoothly varying spatial source density (such as that obtained for randomized arrays or in the presence of source positioning uncertainty or inaccuracy) can yield severe image artifacts. The application of SDA can, thus, yield high image quality even for low channel counts, which can ultimately result in higher imaging frame rates using acquisition systems of reduced complexity.