Experimental evaluation of straight ray and bent ray phase aberration correction for USCT SAFT imaging
Experimental evaluation of straight ray and bent ray phase aberration correction for USCT SAFT imaging
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DOI：
10.1117/12.2292895
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发表时间：
2018-03
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影响因子：
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通讯作者：
T. Hopp;M. Zapf;H. Gemmeke;N. Ruiter
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文献类型：
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作者：
T. Hopp;M. Zapf;H. Gemmeke;N. Ruiter
在超声计算机层析成像（USCT）中，合成孔径聚焦技术（SAFT）常用于反射率图像重建。相位畸变校正对于科普水中和不同人体组织中的大声速差是必不可少的。在本文中，我们比较了两种方法的相位畸变校正：直线近似使用Bresenham算法（B-SAFT）和弯曲光线近似使用多模板快速推进方法（FMM-SAFT）。用模拟的点散射体和模拟的幻影进行分析，以测量对图像分辨率和对比度的影响。该方法还适用于实验数据。B-SAFT降低了图像的分辨率和对比度的情况下，大的声速差异的对象，如果重建点是接近的边界，在阻抗的变化存在。FMM-SAFT是能够恢复在这些情况下，如果声速分布是准确的，并具有高分辨率的图像质量。如果不能满足这些要求，B-SAFT被证明是更强大的。
In Ultrasound computer tomography (USCT) Synthetic aperture focusing technique (SAFT) is often applied for reflectivity image reconstruction. Phase aberration correction is essential to cope with the large sound speed differences in water and the different human tissues. In this paper we compare two approaches for phase aberration correction: a straight ray approximation using the Bresenham algorithm (B-SAFT) and a bent ray approximating using a multi-stencil Fast Marching Method (FMM-SAFT). The analysis is carried out with simulated point scatterers and simulated phantoms to measure the effect on the image resolution and contrast. The method is additionally applied to experimental data. B-SAFT degrades the image resolution and contrast in cases of large sound speed differences of objects and if the reconstructed point is close to a boundary where a change in impedance is present. FMM-SAFT is able to recover the image quality in these cases if the sound speed distribution is known accurately and with high resolution. If these requirements cannot be met, B-SAFT proved to be more robust.