Analytic method based on identification of ellipse parameters for scanner calibration in cone-beam tomography
Analytic method based on identification of ellipse parameters for scanner calibration in cone-beam tomography
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DOI：
10.1088/0031-9155/45/11/327
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发表时间：
2000-11-01
影响因子：
3.5
通讯作者：
Roney, TJ
中科院分区：
文献类型：
--
作者：
Noo, F;Clackdoyle, R;Roney, TJ
本文是关于锥束（CB）扫描器的校准的X射线计算机断层扫描和单光子发射计算机断层扫描。扫描仪校准在这里指的是一组参数的估计，这些参数完全描述了数据采集的几何形状。这样的参数是断层摄影重建步骤所需要的。讨论仅限于圆锥顶点和平面探测器相对于物体沿沿着圆形路径移动的通常情况。还假设检测器不具有空间失真。我们提出了一种新的方法，它需要一个简单的校准对象组成的两个球形对象，可以被认为是“点”对象的一小部分测量。该物体在探测器上跟踪两个椭圆，并且从这些椭圆的参数描述，可以使用显式公式解析地确定校准几何形状。该方法具有鲁棒性强、易于实现等特点。然而，它并不完全通用，因为它假设检测器平行于扫描仪的旋转轴。给出了实验性X射线CB扫描仪的实施细节。
This paper is about calibration of cone-beam (CB) scanners for both x-ray computed tomography and single-photon emission computed tomography. Scanner calibration refers here to the estimation of a set of parameters which fully describe the geometry of data acquisition. Such parameters are needed for the tomographic reconstruction step. The discussion is limited to the usual case where the cone vertex and planar detector move along a circular path relative to the object. It is also assumed that the detector does not have spatial distortions. We propose a new method which requires a small set of measurements of a simple calibration object consisting of two spherical objects, that can be considered as 'point' objects. This object traces two ellipses on the detector and from the parametric description of these ellipses, the calibration geometry can be determined analytically using explicit formulae. The method is robust and easy to implement. However, it is not fully general as it is assumed that the detector is parallel to the rotation axis of the scanner. Implementation details are given for an experimental x-ray CB scanner.