查询词典 backprojection

In this paper we studied filter backprojection algorithm and algebra iteractive algorithm of industrial CT image reconstruction.

本文研究了CT成像的常用算法：滤波反投影算法和代数迭代算法。

We analyzed the main factors that influence on the quality of reconstruction image. These factors are filter function, projection data, sampling space and noise level in filter backprojection, and the choice of relaxation parameter, the fashion of data access, the choice of basis function and the estimate of optimum iterative times in algebra iterative algorithm.

详细分析了影响滤波反投影算法图像重建质量的基本因素(滤波函数的选取，投影数，抽样间距，噪音的大小)和代数重建算法图像重建质量的几个因素(松弛引子的选择，数据访问方式，基函数的选择，最优迭代次数的估计)。

On the basement of conventional direct fan-beam reconstruction, this paper gives a newly improved algorithm-"fast filtering-backprojection". This method utilizes the symmetrical circle geometry to sample projection data, and reconstructs image on the Polarcoordinate firstly, then translates this reconstructed image onto the cartesian coordinate system with two interpolating operations so that the computer can show the result image on the VGA screen. This algorithm rebates the calculating backprojection greatly, and shortens a few times of reconstructing time than same kinds of means. With the size of image enlarging, the reconstructing time abates with 2 exponent times. In addition, according to the idea of parallel-beam, we rearrange the fan-beams and reconstruct image using parallel-beam method fastly. The rearranging constraint condition is given here.

本文首先在传统的扇束直接重建方法的基础上，提出了一个改进的快速滤波反投影重建算法，它利用旋转采集投影数据的圆周对称的几何关系，先在极坐标系统内进行图象的重建，然后通过两次内插运算再将图象转换到计算机显示方式下的笛卡尔坐标系中去，该方法将以往的直接重建方法中的反投影时所需的运算大大降低，并将重建时间比同类方法缩短了几倍，而且随着重建图象的尺寸的增大，重建时间以2的指数次方倍相对缩短，并获得了较好质量的重建图象；另外，又根据平行束投影重建图象的思想，对扇形射束进行了重排，然后利用平行束重建图象的方法进行扇束的重建，并推导了&扇束重排重建图象&方法的约束条件。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。