Geometric calibration for a dual tube/detector micro-CT system
Geometric calibration for a dual tube/detector micro-CT system
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DOI：
10.1118/1.2900000
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发表时间：
2008-05-01
期刊：
影响因子：
3.8
通讯作者：
Badeaa, Cristian T.
中科院分区：
文献类型：
--
作者：
Johnston, Samuel M.;Johnson, G. Allan;Badeaa, Cristian T.
作者描述了一种双管/探测器微型计算机断层扫描(Micro-CT)系统，该系统有可能在小动物成像研究中提高时间分辨率和材料对比度。为了实现这一潜力，有必要精确校准双微CT系统的几何形状，以允许将每个单独的管/探测器获取的投影数据组合在单个重建图像中。作者提出了一种几何校准技术，该技术使用由两个成像链获取的多个投影图像，同时旋转包含规则间隔的金属珠子的垂直阵列的体模。使用分析方法从模型投影图像估计成像链的各个几何形状，然后基于非线性优化的精化过程。几何参数用于为每个成像链创建重建过程所需的锥束投影矩阵。接下来，找到两个投影矩阵之间的变换，该变换允许在单个重建图像中组合投影数据。作者描述了这项技术，用一系列计算机模拟对其进行了测试，然后将其应用于从他们的双管/探测器微型CT系统收集的数据。实验结果表明，该方法具有较高的精确度和较好的鲁棒性，且生成的图像无未对准伪影。(C)2008年美国医学物理学家协会。
The authors describe a dual tube/detector micro-computed tomography (micro-CT) system that has the potential to improve temporal resolution and material contrast in small animal imaging studies. To realize this potential, it is necessary to precisely calibrate the geometry of a dual micro-CT system to allow the combination of projection data acquired with each individual tube/detector in a single reconstructed image. The authors present a geometric calibration technique that uses multiple projection images acquired with the two imaging chains while rotating a phantom containing a vertical array of regularly spaced metallic beads. The individual geometries of the imaging chains are estimated from the phantom projection images using analytical methods followed by a refinement procedure based on nonlinear optimization. The geometric parameters are used to create the cone beam projection matrices required by the reconstruction process for each imaging chain. Next, a transformation between the two projection matrices is found that allows the combination of projection data in a single reconstructed image. The authors describe this technique, test it with a series of computer simulations, and then apply it to data collected from their dual tube/detector micro-CT system. The results demonstrate that the proposed technique is accurate, robust, and produces images free of misalignment artifacts. (C) 2008 American Association of Physicists in Medicine.