Sparse dynamic tomography: a shearlet-based approach for iodine perfusion in plant stems
Sparse dynamic tomography: a shearlet-based approach for iodine perfusion in plant stems
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DOI：
10.1088/1361-6420/ab9c15
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发表时间：
2020-09-01
期刊：
影响因子：
2.1
通讯作者：
Siltanen, Samuli
中科院分区：
文献类型：
--
作者：
Bubba, Tatiana A.;Heikkila, Tommi;Siltanen, Samuli
在本文中，我们提出了一个运动感知的变分方法来重建运动对象从稀疏的动态数据。这项工作的动机源于用液体造影剂灌注的植物的X射线成像，旨在增加图像的对比度并研究植物中的韧皮部运输随时间的推移。我们的方法的关键思想是部署3D剪切波作为时空先验，将时间视为第三维。这种模型背后的基本原理是，卡通类对象的连续演变非常适合使用3D shearlet。我们提供了一个基本的数学分析的变分模型的图像重建。数值最小化进行了原-对偶计划与正则化参数的自动选择。我们在不同的测量设置上测试我们的模型：一个模拟的模型，特别设计成类似于一个植物茎，用扩散点来模拟一个扩散的造影剂;一个测量的琼脂糖凝胶模型，在对活体样本成像之前展示碘化物扩散和几何形状;一个测量的活体树，在体外生长并灌注液体糖碘混合物。与2D静态模型相比，结果表明，我们的方法提供了重建，捕获造影剂发作的时间动态，并鼓励开发microCT作为一种工具，研究韧皮部运输使用碘示踪剂。
In this paper we propose a motion-aware variational approach to reconstruct moving objects from sparse dynamic data. The motivation of this work stems from x-ray imaging of plants perfused with a liquid contrast agent, aimed at increasing the contrast of the images and studying the phloem transport in plants over time. The key idea of our approach is to deploy 3D shearlets as a space-temporal prior, treating time as the third dimension. The rationale behind this model is that a continuous evolution of a cartoon-like object is well suited for the use of 3D shearlets. We provide a basic mathematical analysis of the variational model for the image reconstruction. The numerical minimization is carried out with primal-dual scheme coupled with an automated choice of the regularization parameter. We test our model on different measurement setups: a simulated phantom especially designed to resemble a plant stem, with spreading points to simulate a spreading contrast agent; a measured agarose gel phantom to demonstrate iodide diffusion and geometry prior to imaging living sample; a measured living tree grownin vitroand perfused with a liquid sugar-iodine-mix. The results, compared against a 2D static model, show that our approach provides reconstructions that capture well the time dynamic of the contrast agent onset and are encouraging to develop microCT as a tool to study phloem transport using iodine tracer.