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arXiv 1801.00205physics.med-ph
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用于快速压缩脉冲回波超声成像的随机入射波

Random Incident Waves for Fast Compressed Pulse-Echo Ultrasound Imaging

Martin F. Schiffner

摘要:

在快速超声成像中建立的图像恢复方法,例如延迟求和,以高帧速率换取图像质量。基于压缩感知(CS)的前沿逆散射方法通过先验信息破坏了这种权衡。如果(i)结构构建块的已知字典几乎稀疏地表示图像,并且(ii)由线性模型预测的它们的单独脉冲回波充分不相关,则它们迭代地从仅几个顺序脉冲回波测量或较少回波信号恢复高质量图像。然而,到目前为止,作为转向平面波或柱面波的入射波的排他性建模限制了收敛速度、图像质量和满足条件(ii)的可能性。受压缩感知随机性的影响,提出了一种新的快速压缩采集和图像恢复方法。它恢复弱散射软组织结构中的空间压缩性波动,其中正交基满足条件(i),通过稀疏促进$\ell_{q}$ -最小化方法,$q \in [0; 1]$。一个现实的$d$维模型,$d \in \{2, 3\}$,占衍射,单次散射,幂律吸收和色散的组合,以及一个平面换能器阵列的规格,预测的脉冲回波的各个基函数。三种创新类型的入射波,其合成利用随机变迹权重、时间延迟或其组合,有助于满足条件(ii)。在二维数值模拟中,这些波的单一实现优于普遍的准平面波的正则和傅立叶基。他们显着减少了完整的范围在半最大值的点扩散函数高达73.7%。

英文摘要:

Established image recovery methods in fast ultrasound imaging, e.g. delay-and-sum, trade the image quality for the high frame rate. Cutting-edge inverse scattering methods based on compressed sensing (CS) disrupt this tradeoff via a priori information. They iteratively recover a high-quality image from only a few sequential pulse-echo measurements or less echo signals, if (i) a known dictionary of structural building blocks represents the image almost sparsely, and (ii) their individual pulse echoes, which are predicted by a linear model, are sufficiently uncorrelated. The exclusive modeling of the incident waves as steered plane waves or cylindrical waves, however, has so far limited the convergence speed, the image quality, and the potential to meet condition (ii). Motivated by the benefits of randomness in CS, a novel method for the fast compressed acquisition and the subsequent recovery of images is proposed to overcome these limitations. It recovers the spatial compressibility fluctuations in weakly-scattering soft tissue structures, where an orthonormal basis meets condition (i), by a sparsity-promoting $\ell_{q}$-minimization method, $q \in [0; 1]$. A realistic $d$-dimensional model, $d \in \{2, 3\}$, accounting for diffraction, single monopole scattering, the combination of power-law absorption and dispersion, and the specifications of a planar transducer array, predicts the pulse echoes of the individual basis functions. Three innovative types of incident waves, whose syntheses leverage random apodization weights, time delays, or combinations thereof, aid in meeting condition (ii). In two-dimensional numerical simulations, single realizations of these waves outperform the prevalent quasi-plane wave for both the canonical and the Fourier bases. They significantly reduce the full extents at half maximum of the point spread functions by up to 73.7 %.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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