A Research for Novel Computerized Topography Technologies for Moving Objects.

计算机断层扫描被认为是近十年来最具革命性的医学技术之一。然而，到目前为止提出的算法的能力仅限于重建的二维横截面图像和三维图像的重建已经通过独立地应用这些算法的3-D对象的每个截面图像进行。由于将这些算法独立应用于物体的每一个截面在计算上负担太大，并且不能利用运动物体的截面图像之间的三维相关性来节省计算能力或恢复模糊和噪声投影，因此一直认为使用这些算法从它们的投影重建运动物体是不可能的。我们提出了新的重建算法，以消除上述问题。(1)提出了一种锥束投影直接重建算法，该算法可以比传统方法更快地采集三维数据。该算法还被设计为具有恢复模糊数据的能力。(2)我们开发了一种使用投影之间的冗余结构的降噪技术。当数据由于X射线探测器的快速旋转而有噪声时，该技术是有效的。(3)我们提出了一种新的滤波器，称为部分投影滤波器。该滤波器利用图像的三维相关性来节省数据的采样次数或提高重建图像的质量。

The Computerized Topography is said to be one of the most revolutional medical technologies for the last decade. However, the ability of the algorithms proposed so far is restricted only to the reconstruction of two dimensional cross section images and the reconstruction of 3-dimensional images has been carried out by applying those algorithms independently to each section image of the 3-D objects. It has been thought to be impossible to reconstruct moving objects from their projections by using those algorithms, because the independent application of those algorithms to each section of a object is computationally too much burden and can not make use of the 3-D correlations among the section images of a moving object for saving computation power or for restoring blurred and noisy projections In our research, we proposed novel reconstruction algorithms to eliminate above problems. (1) We proposed a direct reconstruction algorithm for cone beam projection schema by which we can collect 3-D data faster than traditional methods. This algorithm was also designed to have the capability of restoring blurred data. (2) We developed a noise canceling technique which uses the redundant structure among projections. This technique is effective when the data is noisy due to the fast rotation of the X-ray detector. (3) We proposed a new filter which is called a partial projection filter. This filter utilizes the 3-D correlation of images to save the number of samplings of the data or to improve the quality of reconstructed images.