The corresponding image formation algorithms , both in tune domain and frequency domain , are introduced . beginning with the projection reconstruction theory , convolution - backprojection and its approximated algorithm , backprojection algorithm are given 根据这一投影重建理论，导出了impsar目标投影重建的卷积-反投影算法及其近似算法-反向投影算法。
The reconstruction speed of fbp is fast . the image reconstructed by fbp is of high spatial resolution , but with heavy artifacts , while the image reconstructed by art is of high - density resolution and is of sligh artifacts 变换方法以卷积反投影( fbp ）方法最为常用，该算法重建速度快，成像质量较好，但是其要求完全的、等间距的采样数据，通常重建图像伪影较重。
At present , most of the ict systems adopt fbp algorithm which need complete projections of data . in fact , complete projections of data is difficult or even impossible to acquire in many occasions . in this situation , the fbp algorithm is useless 现阶段可实用的ict系统多采用完全投影数据重建的滤波反投影( fbp )算法，而实际中由于客观原因无法检测或很难检测到完全的投影数据，该算法将无能为力。
In inverse problem of ert , the linear back projection algorithm based on sensitivity field is used to reconstruct the qualitative image . assume that the change of conductance is slight , so the sensitivity can be approximately 在电阻层析成像的成像算法方面，论文中使用了基于敏感场的线性反投影算法，假设电导率分布的变化不是很大，则场内敏感场系数的分布可近似的认为不变，这样就可利用敏感场矩阵直接求取多幅图像。
In this paper , we described the two categories of algorithms , especially the fbp algorithm and the emml algorithm . and this paper introduced a new algorithm called maximum entropy ( me ) algorithm . at last , we experimented on computer using some algorithms and got some useful conclusion 本文分别详细介绍了两类算法中常见的一些算法，如滤波反投影法( fbp )和最大似然法( emml )等，并且在此基础上提出了一种新的算法? ?最大熵法。
The parallelization of image reconstruction by convolution back projection with narrow fan - beam based on workstations cluster can solve fast image reconstruction of high power x - ict , and the speed of parallel image reconstruction relates to the numbers of workstations involved 本论文采用窄角扇束卷积反投影图像重建在工作站机群上的并行实现能解决高能x射线工业ct机的快速图像重建问题，并行图像重建的速度与参与并行实现的工作站数有关。
This algorithm not only have the charicristic of local reconstruction that could reduce the amount of x - ray exposure and computations in reconstruction , but could reduce the noise in the conditions of keep same image quality as reconstructed in the filter - backprojection algorithm as well 这种算法具有局部重建特性，从而降低了x射线的辐射剂量和算法的运行时间，在保证和传统的滤波反投影法具有基本相同的图像重建质量的条件下还具有一定的去噪性能。
Re - projection and smooth - transition technology is the kernel of panorama - based virtual reality system . the policy of zooming middle image is introduced to achieve approximate smooth transition animation . an efficient technology of re - projection template is presented in this paper 反投影技术和视点间的平滑过渡技术是基于全景图的虚拟现实系统中的核心技术，本文提出一种简化的策略，通过缩放中间过渡图像得到近似的插值图像，实现了视点间的平滑过渡。
Firstly , unlike the factorization - based methods that minimize the svd ( singular value decomposition ) re - projection error , the method uses the minimization of mean 2d re - projection error of projective points as a criterion , therefore it has a clearer physical meaning and enhances the accuracy of projective reconstruction results 该方法以全局性极小化射影三维空间点的二维反投影误差平方和为准则，相对于缩小svd反投影误差的方法，具有更为明确合理的物理意义。
Prestack migration method , based on wave motion equation , is also developed for receiver function , and compared with ray method . both p - to - s conversion wave and direct p phase contained in receiver function are migrated and imaged by reverse - time migration for data gather including all receiver functions recorded in all seismological stations for one event , and imaging profile is finally obtained by stacking for all events 本文还在接收函数射线反投影叠加成像的基础上，提出了一种基于波动方程的接收函数叠前偏移成像方法，将同一事件接收函数中的转换波和直达p波震相以各自的速度向深度方向逆时延拓成像，并通过不同慢度接收函数的叠加，得到最终的偏移成像结果。
