On the basis of investigation and research about the technology of reconstruction for ict image up - to - date , this paper is devoted to develop an algorithm for image reconstruction based on wavelet theory . in this paper , time - frequency distribution for spatially varying filter was used to construct convolve - kernel by dwt , to modify convolve - back - projection algorithm 本文在国内外有关ct图像重建的研究状况基础上，根据小波分析理论，利用小波变换在时频空间的可变性，用dwt变换构造卷积核，对卷积反投影算法做了改进。
It has avoided 3d rebuild and spherical surface projection and anti - projection etc the problems , and people can with any look at from any viewpoint to view the scene of walk through , and does not need any quicken hardware and just has nothing to do with the complexity of scene , and can be realized on the ordinary microcomputer 它避免了三维重建及球面投影和反投影等问题，人们可以从任何视点以任何视向来观赏漫游场景，不需要任何硬件加速装置且与场景的复杂度无关，可以在普通微机上实现。
Former researchers have done many works in the respect of convolution back projection algorithm . however , according to the result of document retrieval , apart from the study about one the two main problems or a new function used in the reconstruction progress , there is not synthetically study about window function and interpolation methods and effects on quality of ct image 围绕卷积反投影算法的两个问题，前人做了大量的研究，但根据所查阅资料，前人仅就其中一个问题做了一些研究或提出一种新的函数用于图像重建，却并没有全面地分析窗函数与内插函数的特性以及对ct图像的影响情况。
The experimental results of reconstruction from computer - generated projections and real missile tomography projections show that the fast algorithm guarantees the fitness to original image , speeds the iteration time , and can be specially used for reconstruction for incomplete projections in fan scanning 利用模拟投影数据和实际导弹断层扫描数据进行图像重建，结果表明，与卷积反投影和代数重建法相比，此算法特别适用于扇形扫描的不完全投影数据的图像重建，在保证重建图像拟合度的同时，大大提高了重建速度。
This software can be used to construct automatically 16 electrodes and 32 electrical electrodes finite element method ( fem ) division model . the equi - potential lines in any drive pattern can be plotted and the boundary potential changes in its forward problem can be obtained . using back projection method , the impedance imaging in simulation and real measurement can be reconstructed 该软件对任意形状、结构的场域可实现自动剖分，可建立16电极、 32电极求解模型；正问题部分可给出各种激励情况下的等位线分布和边界电位变化情况；逆问题部分用反投影法实现了图像重构，并成功应用于所研制的测试系统。
The method uses the properties of wavelet to reconstruct a local region of the cross section of a body , using almost completely local data , therefore reduces the amount of exposure and computations in reconstruction , while has the same quality as filtered backprojection algorithm 利用小波的特性，该算法仅使用几乎是完全局部的投影数据去重建身体剖面上的某个局部区域，从而大大降低了x射线的辐射剂量和算法的运行时间，同时还具有和传统的滤波反投影法基本相同的图像重建质量。
This thesis developed an algorithm to reconstruct the wavelet coefficients of an image from the radon transform data . this algorithm is similar to the conventional filtered backprojection algorithm , except that the filters are now angle dependent , and the backprojection gives us the wavelet coefficients of the reconstruction , which are then used to synthesize the reconstruction 该算法与传统的滤波反投影法相似，不同的地方在于，算法中用到的滤波器是与x射线的照射角度相关联的，而且反投影后得到的是待建图像的小波分解系数，这些系数再经过逆小波变换就得到了最终的重建图像。
The narrow fan - beams are reset into parallel beam then the image reconstruction is conducted by parallel beam " convolution back projection algorithm , which combines the high scan efficiency with the convenience of image reconstruction . this paper analyses the parallelism in narrow fan - beam " convolution back projection algorithm , divides the task of image reconstruction into several subtasks , and discusses the parallelization of narrow fan - beam " decomposition and reset , parallel beam " convolution back projection , and image accumulation 对于窄角扇束扫描方式，把窄角扇束重排成平行束，再由平行束卷积反投影重建算法来重建图像，是把扫描的高效率和重建方式的简便易行很好的结合起来。本论文对窄角扇束卷积反投影算法进行了并行性分析，指出把图像重建任务分解为多个子任务并行工作，并在工作站机群上讨论了窄角扇束的分解、重排、平行束卷积反投影图像重建、图像合成的并行实现。
The image reconstruction algorithms is thoroughly researched . the filter back projection ( fbp ) , algebra reconstruction technology ( art ) and fan beam data rearrangement algorithm used in medical computer tomography are improved . the noser algorithm , linear neural networks method and hopfield neural networks method are presented and gain the better result of image reconstruction 深入研究了图像重建算法，改进了医学ct的滤波反投影算法、代数重建技术和扇束投影数据重排方法，提出了带图像光滑约束的noser算法、线性神经网络方法和hopfield神经网络方法，并得到了较好的图像重建结果。
Sequentially , the author discussed the technologies of medical image 3d visualization according to the clinical applications . with the development of computer , 3d visualization and computer graphics , the 3d visualization of medical images has progressed from fourier transform and convolve inverse projection to mpr ( multi - planar reformation , mpr ) and mtp ( maximum intensity projection , mtp ) , nowadays , the real 3d reconstruction method , surface and volume rendering has risen . the image registering , image segmentation , pixel data set construction and 3d special interpolation are the key technologies in medical images 3d reconstruction 随着计算机技术、三维可视化理论和计算机图形学的发展，医学图像的三维可视化技术也从傅立叶变换、卷积反投影等基本图像处理算法，发展到真正的三维重建算法：面绘制和体绘制；医学图像的三维可视化技术的应用也从三维医学成像发展到虚拟内窥镜，以及今天的虚拟可视化人体研究；而图像的配准、图像分割、体数据集的构建、三维空间插值则是医学图像三维可视化实现过程中的关键技术环节。
