| 1. | Unfortunately , up to now , there is no an efficient algorithm to deal with the iterative reconstruction algorithm , especially from fan - scanned projections
对于迭代重建，目前尚无很好地解决该问题的算法，特别是对扇束投影重建问题。 |
| 2. | The main disadvantage of iterative algorithm is its slow speed and the time cost of image reconstruction is directly proportional to the number of projections and the size of reconstruction image
迭代重建法最大的缺点是速度慢，其花费时间同投影数的多少以及重建图像的大小成正比。 |
| 3. | But , generally cbp needs complete projection data . algebraic reconstruction to reconstruct ct images has advantages because of its simple arithmetic program and widely using
迭代重建法的算法设计简单,应用范围广,并可以充分利用先验知识进行重建,对不同格式的采样数据,均可以重建 |
| 4. | We performed crosswell tomography on a real crosswell seismic line from shengli oilfield by using simultaneous iterative reconstruction technique ( sirt ) based on shortest path tree ( spt ) curved ray tracing
摘要利用基于最短路径树弯曲射线追踪的联合迭代重建层析成像( sirt )技术进行井间地震层析成像，对胜利油田的一对井间实际资料进行了处理。 |
| 5. | For this method , the matrix inversion and iterative reconstruction are selected based on the quantity and quality of data , and then the physical model and the actually measured data are processed by using this method
层析成像算法根据数据量大小、品质来选择矩阵反演法与迭代重建法，然后对物理模型、实测资料进行层析成像处理，结果获得满意的重建异常体图像。 |
| 6. | In industry application , however , incomplete projections can only be obtained , so the situation is not appropriate to the transformed imaging technique and then the iterative algorithm has to be applied so that better reconstructed image can be got
然而在工业应用中，一般得到的是不完全投影数据，其数量和结构往往无法达到解析成像技术要求的条件，因此为得到较清晰的图像，必须采用迭代重建法。 |
| 7. | A fast and real - time algorithm to obtain some vectors of the projection matrix is proposed in this dissertation to solve the conflict of time cost by matrix obtainment and memory occupied by matrix , and speed the iterative algorithm
作者根据扇形扫描几何的对称性和重叠性，提出了一种快速实时获取投影矩阵分量的方法，较好地解决了获取投影矩阵所需速度和存放其所占内存空间的矛盾，提高了迭代重建算法的速度。 |
| 8. | In order to improve the quality of reconstruction image and solve the problem that " salt and pepper " phenomena occurs in the reconstruction image , the paper proposes a novel algorithm reconstruction technique ( art ) , compare the theory and capability of between them
论文提出新的代数迭代重建算法( art ) ，并且比较了新的重建算法和原有的迭代重建算法的原理和性能，重点研究了在不完全数据重建时， art型算法的性能。 |
| 9. | The authors established an initial velocity model based on the first break time of the actual data , then realized the forward calculation with the improved shortest path ray tracing algorithm , and applied the improved constrained damped simultaneous iterative reconstruction technique ( cdsirt ) to solve large - scale and sparse equations for inversing the near - surface velocity field
根据实际地震数据的初至波时间建立初始速度模型；采用改进的最短路径射线追踪算法进行正演；利用改进的约束带阻尼联合迭代重建技术( cdsirt )求解大型、稀疏的方程组来反演近地表的速度场。 |
