共查询到19条相似文献,搜索用时 109 毫秒
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提出了简单自相关代数迭代重建算法(SSART)。采用数值模拟的方法,对当前有代表性的基本代数迭代法(ART)、联合代数迭代法(SART)、改进的联合代数迭代法(MSART)以及SSART进行了计算模拟,对比分析了各种算法的模拟效果和重建精度。结果发现,SSART的均方误差(MSE)在10^-4数量级,比ART的降低了78.2%;峰值相对误差(PE)在10^-2,降低了92.9%;计算程序上,SSART仅比ART多1个除数因子。所以SSART具有算法简单、重建精度高、稳定性好和自愈能力强等优点。 相似文献
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针对无线信号易受信道影响的难题,将智能反射面(Intelligent Reflecting Surface,IRS)被动波束赋形和基站(Base Station,BS)3D波束赋形进行联合设计。为最大化加权和速率,首先基于投影梯度下降法和加权均方误差等效原理,提出了一种多用户交替优化算法(Multi-User Alternative Optimization,MU-AO),其具有普适性。其次,基于高信噪比(Signal-to-Noise Ratio,SNR)近似原理,提出了一种多用户三级优化算法(Multi-User Three Stage Optimization,MUTSO),通过计算次优组合解来降低计算复杂度。最后,基于BS天线下倾角预定义策略,提出了一种多用户基于直射链路优化算法(Multi-User Direct-Link Based Optimization,MU-DLBO),能够实现复杂度与性能的均衡。实验表明,所提算法均能有效提升系统加权和速率,体现了联合波束赋形的有效性。 相似文献
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利用康普顿散射可以重建物质的电子密度图像。传统的逐点重建法算法简单,但实验装置复杂,且存在对焦误差,文章对传统的逐点重建成像方法进行了改进,提出了基于行扫描散射能谱的逐点重建方法,在此基础上用对称校正的方法对重建结果进行了改善,并给出了计算机仿真的结果。 相似文献
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数字全息显微中常见重建算法比较 总被引:1,自引:0,他引:1
基于理论分析和实验验证相结合的方法,对数字全息显微术中常见的三种重建算法即菲涅耳变换算法、角谱算法和卷积算法做了比较研究。结果表明:利用菲涅耳变换算法对离轴无透镜傅里叶变换数字全息进行重建时,无重建距离的限制;采用卷积重建法只能在最佳再现距离附近一个非常小的范围内才能获得高分辨率再现像;而采用角谱重建法在略小于最佳再现距离及大于最佳再现距离较大范围内重建,均能获得高分辨率的再现像。角谱重建法总体上优于卷积重建法。菲涅耳变换重建法简单、快捷,是优化的重建算法。 相似文献
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由于太赫兹波具有独特的性质,使得太赫兹成像技术成为目前的研究热点。太赫兹层析成像可以获得物体横截面的分布信息并可获得物体的三维重构图像,因此也受到了广泛关注。文中对连续太赫兹层析成像进行了仿真研究。分别使用滤波反投影算法(FBP)和改进的联合代数重建算法(MSART)进行图像重构,并且分析比较了高斯低通滤波(GLPF)以及数学形态学等数字图像处理方法对改善重构图像质量的效果。仿真结果表明:在文中的仿真条件下,使用MSART算法及相应的图像处理方法所需的最少投影方向数可以达到9,与真实成像实验结果相吻合。 相似文献
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Reconstructing non-ideal-bordered field by simple self-correlative algebraic reconstruction technique 总被引:1,自引:0,他引:1
SONG Yi-zhong ZHANG Bin FU Lin HE An-zhi 《光电子快报》2006,2(1):63-67
A new algorithm for iterative reconstruction is suggested. It is named simple self-correlative algebraic reconstruction technique (SSART). With numerical simulation experiments, SSART was applied in reconstructing a non-ideal-bordered field in order to test its reconstructive effect, For contrast, three current representative algebraic reconstruction(ARTs) including basic ART, simultaneous ART (SART) and modified SART (MSART) were simulated simultaneously. The calculated results and reconstructive accuracy are discussed with three kinds of error indexes, namely mean-square error (MSE), absolute value error (AVE) and peak error (PE). As the results, the indexes of reconstructive accuracy are much improved by the proposed SSART. The MSE and PE have been decreased by 63.6% on the order of magnitude 10-4 and 88.9% on the order of magnitude 0-2,respectively,compared to that of ART. It is concluded that SSART is one of the most super iterative reconstructing techniques. 相似文献
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有限角CT少数投影重建图像技术 总被引:9,自引:4,他引:5
叙述了有限角CT少数投影重建图像技术研究所取得的进展:正交全息光路、干涉条纹处理系统、修改的联合代数重建技术、频谱分析图像重建技术和神经网络重建技术。 相似文献
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Overview on Technical Issues for Future Mobile Network and a Proposal of DLC Scheme in Wireless Link
This paper gives an overview on technical issues for future mobile networks. the QoS control for multimedia services, security function, expansion of network capacity, expansion of address space, multicast function, radio link quality and mobility control of terminals are taken up as technical issues.Then, a novel DLC scheme in wireless link named EREP-ARQ (Estimation and Report of Error Pattern ARQ) which can reduce the retransmission ratio is proposed. In this scheme, error pattern generated in the radio link is estimated at the receiver side and the estimated error pattern is returned to the transmission side. If the estimation is correct, no retransmission is needed. Compared to conventional SR-ARQ, throughput can be improved by17% and Cell Loss Ratio (or Packet Loss Rate) can be reduced to less than 1/10 by the proposed EREP-ARQ. 相似文献
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Terahertz Computed Tomography Using A Continuous-Wave Gas Laser 总被引:1,自引:0,他引:1
Qi Li Yun-Da Li Sheng-Hui Ding Qi Wang 《Journal of Infrared, Millimeter and Terahertz Waves》2012,33(5):548-558
A 3D continuous-wave (CW) terahertz computed tomography (CT) system employing a gas laser operating at 2.52 THz is presented.
To shorten acquisition time on the premise of guaranteeing the image quality, the modified simultaneous algebraic reconstruction
technique (MSART) coupled with image processing operations like the Gaussian low-pass filter (GLPF), open operation and close
operation has been adopted in the paper. With the 2D results the 3D images of the samples have been also obtained. The reconstruction
results illustrate the promising application prospects of this CW THz CT system. 相似文献
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利用二元光学器件进行激光光强叠加的研究 总被引:1,自引:1,他引:0
以1-维为例,采用杨-顾算法研究了利用二元光学技术进行激光光强叠加的可能性,并分析了由于蚀刻误差和入射激光束位置偏度引起的误差,数值模拟结果表明在DOE位相是32阶是化的情况下,设计误差小于0.08%,效率大于99.70%,能很好地实现光强叠加功能。 相似文献
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In this paper, we propose a new factorization-based algorithm for projective reconstruction from multiple views by minimizing
the 2D reprojection error in the images. In our algorithm, the projective reconstruction problem is formulated as a constrained
minimization problem, which minimizes the 2D reprojection error in multiple images. To solve this constrained minimization
problem, we use the augmented Lagrangian approach to generate a sequence of unconstrained minimization problems, which can
be readily solved by standard least-squares technique. Thus we can estimate the projective depths, the projection matrices
and the positions of 3D points simultaneously by iteratively solving a sequence of unconstrained minimization problems. The
proposed algorithm does not require the projective depths as prior knowledge, unlike bundle adjustment techniques. It converges
more robustly and rapidly than the penalty based method. Furthermore, it readily handles the case of partial occlusion, where
some points cannot be observed in some images. 相似文献