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Geometrically Nonlinear Deformation Reconstruction Based on iQS4 Elements Using a Linearized Iterative iFEM Algorithm 认领 引用 被引量：4
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作者 Mengying Li Dawei Jia +2 位作者 He Huang Ziyan Wu Adnan Kefal 《Acta Mechanica Solida Sinica》 SCIE EI CSCD 2023年第1期166-180,共15页
Structural shape monitoring plays a vital role in the structural health monitoring systems.The inverse finite element method(iFEM)has been demonstrated to be a practical method of deformation reconstruction owing to i... Structural shape monitoring plays a vital role in the structural health monitoring systems.The inverse finite element method(iFEM)has been demonstrated to be a practical method of deformation reconstruction owing to its unique advantages.Current iFEM formulations have been applied to small deformation of structures based on the small-displacement assumption of linear theory.However,this assumption may be inapplicable to some structures with large displacements in practical applications.Therefore,geometric nonlinearity needs to be considered.In this study,to expand the practical utility of iFEM for large displacement monitoring,we propose a nonlinear iFEM algorithm based on a four-node inverse quadrilateral shell element iQS4.Taking the advantage of an iterative iFEM algorithm,a nonlinear response is linearized to compute the geometrically nonlinear deformation reconstruction,like the basic concept of nonlinear FE analysis.Several examples are solved to verify the proposed approach.It is demonstrated that large displacements can be accurately estimated even if the in-situ sensor data includes different levels of randomly generated noise.It is proven that the nonlinear iFEM algorithm provides a more accurate displacement response as compared to the linear iFEM methodology for structures undergoing large displacement.Hence,the proposed approach can be utilized as a viable tool to effectively characterize geometrically nonlinear deformations of structures in real-time applications. 展开更多
关键词 Deformation reconstruction iQS4 element Iterative algorithm Nonlinear iFEM Geometric nonlinearity
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Fast parallel algorithm for three-dimensional distance-driven model in iterative computed tomography reconstruction 认领 引用 被引量：1
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作者 陈建林 李磊 +5 位作者 王林元 蔡爱龙 席晓琦 张瀚铭 李建新 闫镔 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第2期513-520,共8页
The projection matrix model is used to describe the physical relationship between reconstructed object and projection.Such a model has a strong influence on projection and backprojection,two vital operations in iterat... The projection matrix model is used to describe the physical relationship between reconstructed object and projection.Such a model has a strong influence on projection and backprojection,two vital operations in iterative computed tomographic reconstruction.The distance-driven model（DDM） is a state-of-the-art technology that simulates forward and back projections.This model has a low computational complexity and a relatively high spatial resolution;however,it includes only a few methods in a parallel operation with a matched model scheme.This study introduces a fast and parallelizable algorithm to improve the traditional DDM for computing the parallel projection and backprojection operations.Our proposed model has been implemented on a GPU（graphic processing unit） platform and has achieved satisfactory computational efficiency with no approximation.The runtime for the projection and backprojection operations with our model is approximately 4.5 s and 10.5 s per loop,respectively,with an image size of 256×256×256 and 360 projections with a size of 512×512.We compare several general algorithms that have been proposed for maximizing GPU efficiency by using the unmatched projection/backprojection models in a parallel computation.The imaging resolution is not sacrificed and remains accurate during computed tomographic reconstruction. 展开更多
关键词 computed tomography iterative reconstruction parallelizable algorithm distance-driven model
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Preliminary clinical application of an adaptive iterative statistical reconstruction algorithm inhead and neck computed tomography angiography with low tube voltage and a low concentration of contrast medium 认领 引用 被引量：2
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作者 Shan Hu Wenzhen Zhu +4 位作者 Daoyu Hu XiaoYan Meng Jinhua Zhang Weijia Wan Li Zhou 《Oncology and Translational Medicine》 CAS 2015年第4期171-176,共6页
Objective To evaluate the feasibility of using a low concentration of contrast medium （Visipaque 270 mgl/mL）, low tube voltage, and an advanced image reconstruction algorithm in head and neck computed tomography ang... Objective To evaluate the feasibility of using a low concentration of contrast medium （Visipaque 270 mgl/mL）, low tube voltage, and an advanced image reconstruction algorithm in head and neck computed tomography angiography （CTA）. Methods Forty patients （22 men and 18 women; average age 48.7 ± 14.25 years; average body mass index 23.9 ± 3.7 kg/m^2） undergoing CTA for suspected vascular diseases were randomly assigned into two groups. Group A （n = 20） was administered 370 mgl/mL contrast medium, and group B （n = 20） was administered 270 mgl/mL contrast medium. Both groups were administered at a rate of 4.8 mL/s and an injection volume of 0.8 mL/kg. Images of group A were obtained with 120 kVp and filtered back projection （FBP） reconstruction, whereas images of group B were obtained with 80 kVp and 80% adaptive iterative statistical reconstruction algorithm （ASiR）. The CT values and standard deviations of intracranial arteries and image noise on the corona radiata were measured to calculate the contrast-to-noise ratio （CNR） and signal-to-noise ratio （SNR）. The beam-hardening artifacts （BHAs） around the skull base were calculated. Two readers evaluated the image quality with volume rendered images using scores from 1 to 5. The values between the two groups were statistically compared. Results The mean CT value of the intracranial arteries in group B was significantly higher than that in group A （P 〈 0.001）. The CNR and SNR values in group B were also statistically higher than those in group A （P 〈 0.001）. Image noise and BHAs were not significantly different between the two groups. The image quality score of VR images of in group B was significantly higher than that in group A （P = 0.001）. However, the quality scores of axial enhancement images in group B became significantly smaller than those in group A （P〈 0.001）. The CT dose index volume and dose-length product were decreased by 63.8% and 64%, respectively, in group B （P 〈 0.001 for both）. Conclusion Visipaque combined with 80 kVp and 80% ASiR provided similar image quality in intracranial CTA with 64% radiation dose reduction compared with the use of lopamidol, 120 kVp, and FBP reconstruc-tion. 展开更多
关键词 low concentration contrast medium head and neck computed tomography angiography adaptive iterative statistical reconstruction algorithm
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Electrical Impedance Tomography Image Reconstruction Using Iterative Lavrentiev and L-Curve-Based Regularization Algorithm 认领 引用
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作者 Wenqin WANG Jingye CAI Lian YANG 《Journal of Electromagnetic Analysis and Applications》 2010年第1期45-50,共6页
Electrical impedance tomography (EIT) is a technique for determining the electrical conductivity and permittivity distribution inside a medium from measurements made on its surface. The impedance distribution reconstr... Electrical impedance tomography (EIT) is a technique for determining the electrical conductivity and permittivity distribution inside a medium from measurements made on its surface. The impedance distribution reconstruction in EIT is a nonlinear inverse problem that requires the use of a regularization method. The generalized Tikhonov regularization methods are often used in solving inverse problems. However, for EIT image reconstruction, the generalized Tikhonov regularization methods may lose the boundary information due to its smoothing operation. In this paper, we propose an iterative Lavrentiev regularization and L-curve-based algorithm to reconstruct EIT images. The regularization parameter should be carefully chosen, but it is often heuristically selected in the conventional regularization-based reconstruction algorithms. So, an L-curve-based optimization algorithm is used for selecting the Lavrentiev regularization parameter. Numerical analysis and simulation results are performed to illustrate EIT image reconstruction. It is shown that choosing the appropriate regularization parameter plays an important role in reconstructing EIT images. 展开更多
关键词 Electrical Impedance Tomography (EIT) Reconstruction Algorithm Iterative Lavrentiev Regularization Parameter Inverse Problem.
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Randomized Kaczmarz algorithm for CT reconstruction 认领 引用 被引量：1
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作者 赵可 潘晋孝 孔慧华 《Journal of Measurement Science and Instrumentation》 CAS 2013年第1期34-37,共4页
The order of the projection in the algebraic reconstruction technique(ART)method has great influence on the rate of the convergence.Although many scholars have studied the order of the projection,few theoretical proof... The order of the projection in the algebraic reconstruction technique(ART)method has great influence on the rate of the convergence.Although many scholars have studied the order of the projection,few theoretical proofs are given.Thomas Strohmer and Roman Vershynin introduced a randomized version of the Kaczmarz method for consistent,and over-determined linear systems and proved whose rate does not depend on the number of equations in the systems in 2009.In this paper,we apply this method to computed tomography(CT)image reconstruction and compared images generated by the sequential Kaczmarz method and the randomized Kaczmarz method.Experiments demonstrates the feasibility of the randomized Kaczmarz algorithm in CT image reconstruction and its exponential curve convergence. 展开更多
关键词 Kaczmarz method iterative algorithm randomized Kaczmarz method computed tomography(CT) CT image reconstruction exponent curve fitting
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A projection-domain iterative algorithm for metal artifact reduction by minimizing the total-variation norm and the negative-pixel energy 认领 引用 被引量：2
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作者 Gengsheng L.Zeng 《Visual Computing for Industry,Biomedicine,and Art》 EI 2022年第1期1-11,共11页
Metal objects in X-ray computed tomography can cause severe artifacts.The state-of-the-art metal artifact reduction methods are in the sinogram inpainting category and are iterative methods.This paper proposes a proje... Metal objects in X-ray computed tomography can cause severe artifacts.The state-of-the-art metal artifact reduction methods are in the sinogram inpainting category and are iterative methods.This paper proposes a projectiondomain algorithm to reduce the metal artifacts.In this algorithm,the unknowns are the metal-affected projections,while the objective function is set up in the image domain.The data fidelity term is not utilized in the objective function.The objective function of the proposed algorithm consists of two terms:the total variation of the metalremoved image and the energy of the negative-valued pixels in the image.After the metal-affected projections are modified,the final image is reconstructed via the filtered backprojection algorithm.The feasibility of the proposed algorithm has been verified by real experimental data. 展开更多
关键词 Analytical image reconstruction Metal artifact reduction Projection-domain iterative algorithm X-ray computed tomography
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Radar Imaging Based on Iterative Algorithms 认领 引用
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作者 Qiangfu Zhao, Zhong Wang and Youan KeDept. of Electronic Eng., Beijing Institute of Technology, P.O.Box 327, Beijing 100081, China 《Journal of Systems Engineering and Electronics》 1991年第2期91-99,共9页
It has long been realized that the problem of radar imaging is a special case of image reconstruction in which the data are incomplete and noisy. In other fields, iterative reconstruction algorithms have been used suc... It has long been realized that the problem of radar imaging is a special case of image reconstruction in which the data are incomplete and noisy. In other fields, iterative reconstruction algorithms have been used successfully to improve the image quality. This paper studies the application of iterative algorithms in radar imaging. A discrete model is first derived, and the iterative algorithms are then adapted to radar imaging. Although such algorithms are usually time consuming, this paper shows that, if the algorithms are appropriately simplified, it is possible to realize them even in real time. The efficiency of iterative algorithms is shown through computer simulations. 展开更多
关键词 Radar imaging Computerized tomography Discrete model Iterative reconstruction algorithm Algebraic reconstruction technique.
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Iterative analytic extension in tomographic imaging 认领 引用
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作者 Gengsheng L.Zeng 《Visual Computing for Industry,Biomedicine,and Art》 EI 2022年第1期44-56,共13页
If a spatial-domain function has a finite support,its Fourier transform is an entire function.The Taylor series expansion of an entire function converges at every finite point in the complex plane.The analytic continu... If a spatial-domain function has a finite support,its Fourier transform is an entire function.The Taylor series expansion of an entire function converges at every finite point in the complex plane.The analytic continuation theory suggests that a finite-sized object can be uniquely determined by its frequency components in a very small neighborhood.Trying to obtain such an exact Taylor expansion is difficult.This paper proposes an iterative algorithm to extend the measured frequency components to unmeasured regions.Computer simulations show that the proposed algorithm converges very slowly,indicating that the problem is too ill-posed to be practically solvable using available methods. 展开更多
关键词 Analytic continuation Entire function Iterative projections onto convex sets algorithm Image reconstruction Limited angle tomography
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多模型迭代重建算法在宽体探测器CT中行双低剂量头颈CTA联合全脑CTP一站式检查的可行性 认领 引用 被引量：1
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作者 祁冬 李娟 +2 位作者 司峥 杨米雪 崔悦 《医学影像学杂志》 2026年第3期137-142,共6页
目的探讨多模型迭代重建(ASiR-V)算法在宽体探测器CT中行双低剂量头颈CT血管成像(CTA)联合全脑CT灌注成像(CTP)一站式检查的可行性。方法选取疑似急性缺血性脑卒中(AIS)患者84例,按照随机数字表法随机分为A、B、C三组,每组28例。在双低... 目的探讨多模型迭代重建(ASiR-V)算法在宽体探测器CT中行双低剂量头颈CT血管成像(CTA)联合全脑CT灌注成像(CTP)一站式检查的可行性。方法选取疑似急性缺血性脑卒中(AIS)患者84例,按照随机数字表法随机分为A、B、C三组,每组28例。在双低剂量头颈CTA联合全脑CTP一站式检查中,A组管电压100 kV、对比剂碘海醇(碘浓度350 mg/mL)、图像重建FBP算法,B组管电压80 kV、对比剂碘克沙醇(碘浓度320 mg/mL)、图像重建FBP算法,C组管电压80 kV、对比剂碘克沙醇(碘浓度320 mg/mL)、图像重建ASiR-V算法。比较三组头颈CTA和全脑CTP扫描参数、图像质量主观评分,分析三组图像质量主观评价和客观评价一致性,并比较三组辐射剂量和碘摄入量。结果与A组比较,B组同部位CT值标准差(SD)升高(P均<0.05),同部位信噪比(SNR)、对比噪声比(CNR)降低(P均<0.05);与B组比较,C组同部位SD降低,同部位SNR、CNR升高(P均<0.05)。与A组比较,B组同部位脑血流量(CBF)、脑血容量(CBV)、达峰反应时间(Tmax)降低(P均<0.05);与B组比较,C组同部位CBF、CBV、Tmax升高(P均<0.05)。B组头颈CTA、全脑CTP图像质量主观评分均低于A、C组(P均<0.05)。2位医师对三组头颈CTA和全脑CTP图像质量主观评价的一致性很好(Kappa分别为0.812、0.809)。医师内ICC分析显示,SNR、CBF、Tmax的一致性好(ICC分别为0.782、0.805、0.812);医师间ICC分析显示,CNR、CBV、Tmax的一致性好(ICC分别为0.831、0.791、0.855)。与A组比较,B、C组容积CT剂量指数、CT剂量长度乘积、有效辐射剂量及碘摄入量均降低(P均<0.05)。结论ASiR-V算法在宽体探测器CT中行双低剂量头颈CTA联合全脑CTP一站式检查具有可行性,不仅能获得满意的图像质量,还能降低辐射剂量和碘摄入量。 展开更多
关键词 体层摄影术,X线计算机 血管成像 灌注成像 急性缺血性脑卒中 宽体探测器 多模型迭代重建算法
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不同重建算法对CT血管造影图像质量影响的体模研究 认领 引用
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作者 杨创勃 苏业明 +4 位作者 孟欣欣 张敏 马光明 于楠 贾永军 《分子影像学杂志》 2026年第3期362-367,共6页
目的比较不同权重混合迭代重建(ASIR-V)和深度学习图像重建(DLIR)CT血管造影(CTA)图像质量,探讨DLIR在优化CTA中的优势和潜力。方法采用Apex CT扫描含有9支试管的QSP体模,实验试管选择为1支纯水和5支碘溶液(其中30 mg/mL碘溶液2支,浓度... 目的比较不同权重混合迭代重建(ASIR-V)和深度学习图像重建(DLIR)CT血管造影(CTA)图像质量,探讨DLIR在优化CTA中的优势和潜力。方法采用Apex CT扫描含有9支试管的QSP体模,实验试管选择为1支纯水和5支碘溶液(其中30 mg/mL碘溶液2支,浓度为3.75、7.5、15 mgI/mL各1支),分别用0%~100%(间隔10%)共11种权重标准卷积核ASIR-V和3种权重标准卷积核DLIR(DLIR-L/M/H)重建1.25 mm CTA图像。选取实验试管中的9个固定水平放置感兴趣的区域,以纯水的标准差(SD)值作为背景噪声,测量目标试管中的纯水和碘溶液CT值。计算并比较不同权重两种算法重建对纯水CT值和碘溶液图像CT值、噪声和对比噪声比(CNR)的影响。比较体模中心和体模边缘30 mgI/mL碘溶液平均CT值、噪声和CNR。结果不同权重2种算法重建图像中纯水和各种碘浓度溶液CT值的差异无统计学意义(P>0.05),体模中心与体模边缘30 mgI/mL碘溶液比较,CT值和CNR均下降(P0.05)外,不同权重2种算法重建图像噪声不同(P0.05)。ASIR-V 80%、ASIR-V 90%与DLIR-M重建图像的噪声差异无统计学意义(P>0.05)。除相邻10%的0%~60%ASIR-V权重间重建图像CNR差异无统计学意义外,随着ASIR-V和DLIR权重的增加,各种碘浓度溶液CNR增加,其中DLIR-H的CNR最大。ASIR-V 60%、ASIR-V 70%与DLIR-L重建图像CNR差异无统计学意义(P>0.05),ASIR-V 90%与DLIR-M重建图像的CNR差异无统计学意义(P>0.05)。结论DLIR在不改变CT值的情况下可提高CTA图像质量,DLIR-H噪声最低,CNR最大。 展开更多
关键词 体层摄影术 X线计算机 血管造影术 算法 迭代重建技术
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基于侧扫声呐图像的水下3维地形环境重建 认领 引用
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作者 张兰勇 刘振林 路紫葳 《机器人》 EI CSCD 北大核心 2026年第3期443-451,共9页
为了能够360◦展现海底地形环境和海底目标的3维立体空间形态,设计了基于BFGS(Broyden-Fletcher-Goldfarb-Shanno)法和交替方向乘子法的明暗恢复形状(SFS)3维重建方法。通过该方法和预处理共轭梯度迭代优化算法对2维侧扫声呐图像进行迭代... 为了能够360◦展现海底地形环境和海底目标的3维立体空间形态,设计了基于BFGS(Broyden-Fletcher-Goldfarb-Shanno)法和交替方向乘子法的明暗恢复形状(SFS)3维重建方法。通过该方法和预处理共轭梯度迭代优化算法对2维侧扫声呐图像进行迭代,处理相关约束条件,确保最终3维重建结果的一致性与平滑性。得到3维重建的水下地形图后,建立了3维重建算法指标,同时进行了一系列实验验证,确保所提出的SFS三维重建方法不仅在理论上切实可行,而且实践效果显著,满足水下3维地形重建的需求。 展开更多
关键词 3维重建 侧扫声呐图像 迭代算法 明暗恢复形状
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非相干全息-偏振融合的水下计算成像方法及其自适应散射抑制 认领 引用 被引量：1
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作者 尹皓 于雪莲 +3 位作者 孙彦乾 牛佳 李秀芳 贺磊 《光学学报》 EI CAS CSCD 北大核心 2026年第12期261-271,共11页
针对浑浊水体中后向散射导致的成像对比度严重退化及细节结构丢失问题,提出一种非相干全息-偏振融合的水下计算成像方法。该方法利用非相干全息编码记录目标光场信息,通过非线性重建在频域内抑制以散射为主导的低频背景分量,从成像物理... 针对浑浊水体中后向散射导致的成像对比度严重退化及细节结构丢失问题,提出一种非相干全息-偏振融合的水下计算成像方法。该方法利用非相干全息编码记录目标光场信息,通过非线性重建在频域内抑制以散射为主导的低频背景分量,从成像物理层面增强目标结构信息的可辨识性。在此基础上,将重建的正交偏振强度图像引入水下偏振成像物理模型,实现后向散射分量的稳定估计与去除。针对物理模型复原后仍可能存在的非均匀散斑噪声,引入含各向异性扩散约束的非相干非线性解卷积迭代算法,在固定频谱相位与空域支撑约束下实现噪声抑制与边缘细节保持的协同优化。实验结果表明,在不同浊度条件下,所提方法相较传统水下偏振成像方法能够获得更高的信噪比与结构保真度,尤其在高浑浊环境中表现出更强的散射抑制能力与分辨率保持性能,验证了其在复杂水下环境中实现高质量水下光学成像的有效性。 展开更多
关键词 无干涉编码孔径相关全息 水下偏振成像 非线性重建 非相干非线性解卷积迭代算法
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深度学习重建算法在低剂量冠状动脉CT血管成像中的图像质量与辐射剂量优化:一项前瞻性随机对照研究 认领 引用 被引量：2
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作者 杨欢 周永霞 +1 位作者 丁昭军 刘文罡 《中国医学装备》 2026年第2期13-17,共5页
目的:比较低管电流结合深度学习重建(DLIR)算法与低管电流结合混合迭代重建(HIR)算法和常规扫描方案结合HIR算法所获得的冠状动脉CT血管成像(CCTA)的图像,评估DLIR算法在CCTA中的临床应用价值。方法:前瞻性纳入2023年8月至2024年5月重... 目的:比较低管电流结合深度学习重建(DLIR)算法与低管电流结合混合迭代重建(HIR)算法和常规扫描方案结合HIR算法所获得的冠状动脉CT血管成像(CCTA)的图像,评估DLIR算法在CCTA中的临床应用价值。方法:前瞻性纳入2023年8月至2024年5月重庆医科大学附属永川医院收治的100例拟行回顾性门控CCTA检查的患者,采用随机数表法将其分为常规剂量组(50例)和低剂量组(50例)。常规剂量组采用160 mAs扫描,并以迭代重建算法进行图像重建。低剂量组采用60 mAs扫描,将该组患者的扫描数据分别采用两种不同的算法进行重建,又分为A组和B组,A组采用Karl 3D、B组使采用DLIR算法。比较常规剂量组、A组和B组3组的辐射剂量、主观图像质量评价、客观图像质量测量值图像噪声(SD)、信噪比(SNR)、对比噪声比(CNR)。结果:低剂量组(A和B组)有效辐射剂量(4.29±0.90)m Sv显著低于常规组(9.38±1.90)m Sv(t=17.10,P0.05),常规剂量组和B组的图像质量均优于A组,差异有统计学意义(x2=39.71、46.22,P0.05);常规剂量组、A组和B组噪声比较差异有统计学意义(F=176.39,P<0.05),冠状动脉各节段[右冠状动脉(RCA);左前降支(LAD);左旋支(LCX)]SNR和CNR比较差异均具有统计学意义(F=132.79、129.36、133.37和161.23、170.68、169.64,P<0.05)。结论:低管电流结合DLIR算法应用于回顾性门控CCTA中,可以显著降低辐射剂量,并进一步提高图像质量。 展开更多
关键词 冠状动脉CT血管成像(CCTA) 深度学习重建(DLIR)算法 混合迭代重建(HIR) 辐射剂量
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Landweber Iterative Methods for Angle-limited Image Reconstruction 认领 引用 被引量：4
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作者 Gang-rong Qu Ming Jiang 《Acta Mathematicae Applicatae Sinica》 SCIE 2009年第2期327-334,共8页
We introduce a general iterative scheme for angle-limited image reconstruction based on Landwebet＇s method. We derive a representation formula for this scheme and consequently establish its convergence conditions. Ou... We introduce a general iterative scheme for angle-limited image reconstruction based on Landwebet＇s method. We derive a representation formula for this scheme and consequently establish its convergence conditions. Our results suggest certain relaxation strategies for an accelerated convergence for angle-limited image reconstruction in L^2-norm comparing with alternative projection methods. The convolution-backprojection algorithm is given for this iterative process. 展开更多
关键词 The Landweber iteration angle-limited image reconstruction the selections of relaxation coefficients convolution-backprojection algorithm
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快中子层析成像与锥束几何三维重建算法研究 认领 引用
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作者 邢胜玉 卢棚 +3 位作者 刘源煜 李佳 梁立振 洪兵 《哈尔滨商业大学学报（自然科学版）》 CAS 2026年第1期51-58,共8页
中子层析成像利用中子透射物体的特征,根据中子透射强度信息进行图像重建,分析内部结构.聚焦三维锥束几何的中子层析图像进行图像重建,通过粒子输运程序模拟得到快中子透射数据,利用滤波反投影算法(FDK)、同步代数重建(SART)、有序子集... 中子层析成像利用中子透射物体的特征,根据中子透射强度信息进行图像重建,分析内部结构.聚焦三维锥束几何的中子层析图像进行图像重建,通过粒子输运程序模拟得到快中子透射数据,利用滤波反投影算法(FDK)、同步代数重建(SART)、有序子集同步代数重建(OSSART)、同步迭代重建(SIRT)、最小二乘QR分解(LSQR)算法进行图像重建,使用结构相似性指数(SSIM)等指标,比较分析了各类算法在不同投影角度数量的图像重建效果.结果表明,在不同投影图片数量条件下,FDK算法重建效率显著优于迭代算法;在稀疏投影场景中,SIRT算法的综合表现相对较好.研究为后续快中子三维重建算法优化奠定基础. 展开更多
关键词 快中子 锥束几何 迭代算法 三维重建 FDK
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基于X-Ray图像的榴莲内部结构三维重建与分割 认领 引用
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作者 卢昊阳 张志飞 +1 位作者 郭龙辉 侯北平 《浙江科技大学学报》 2026年第3期269-280,共12页
【目的】榴莲内部结构复杂、密度不均导致传统二维X-ray图像无法完整表征其三维信息,且现有重建与分割方法存在伪影多、精度低、效率不高等问题,对此提出并设计了榴莲内部结构的快速、高精度三维重建与精确分割方法及系统。【方法】首先... 【目的】榴莲内部结构复杂、密度不均导致传统二维X-ray图像无法完整表征其三维信息,且现有重建与分割方法存在伪影多、精度低、效率不高等问题,对此提出并设计了榴莲内部结构的快速、高精度三维重建与精确分割方法及系统。【方法】首先,构建了榴莲X-ray图像采集与处理系统;其次,提出了FDK-SIRT联合重建算法,融合三维FDK(Feldkamp-Davis-Kress,费尔德坎普-戴维斯-克雷斯)重建算法与同步迭代重建技术(simultaneous iterative reconstruction technique,SIRT),以提升重建质量与效率;最后,提出了ASPP-U-KAN分割模型,在U-Net架构基础上引入空洞空间金字塔池化(atrous spatial pyramid pool,ASPP)模块,并采用柯尔莫哥洛夫-阿诺德网络(Kolmogorov-Arnold network,KAN)和深度可分离卷积(depthwise separable convolution,DSC)构建高效特征提取模块,以提升训练效率和分割精度。【结果】试验结果表明,FDK-SIRT算法的结构相似性指数(structure similarity index measure,SSIM)较SIRT、SART(simultaneous algebraic reconstruction technique,联合代数重建技术)和FDK算法分别提高9.28%、8.25%和18.06%,虽然比MedNeRF(medical neural radiance fields,医学神经辐射场)算法低0.92%,但重建时间大幅减少。ASPP-U-KAN模型在榴莲果肉分割任务中的交并比(intersection over union,IoU)达到95.1%,且训练时间缩至3320 s。【结论】本研究提出的算法能有效实现榴莲内部结构的高质量三维重建及精确、高效分割,从而为榴莲内部缺陷无损检测与品质评估提供了可行的技术方案。 展开更多
关键词 榴莲内部结构 X-ray图像 三维重建 图像分割 FDK算法 同步迭代重建技术 KAN网络
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头颈部CTA采用FIRST算法与FBP算法对图像质量的影响 认领 引用
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作者 田原 赵瑞 刘康康 《影像技术》 CAS 2026年第2期74-79,共6页
目的:探讨头颈部CT血管成像(CTA)检查中应用全模型迭代重建(FIRST)算法与滤波反投影(FBP)算法对图像质量的影响。方法:前瞻性选取2022年10月-2024年8月我院接诊的160例行头颈部CTA检查的患者,对原始图像以不同的算法进行重建,分为FBP组(... 目的:探讨头颈部CT血管成像(CTA)检查中应用全模型迭代重建(FIRST)算法与滤波反投影(FBP)算法对图像质量的影响。方法:前瞻性选取2022年10月-2024年8月我院接诊的160例行头颈部CTA检查的患者,对原始图像以不同的算法进行重建,分为FBP组(FBP算法)、FIRST组(FIRST算法),对比两组主观图像质量评分、客观图像质量参数[信噪比(SNR)、对比噪声比(CNR)]、辐射剂量参数[容积CT剂量指数(CTDIvol)、剂量长度乘积(DLP)、有效剂量(ED)]以及诊断效能。结果:与FBP组相比,FIRST组的各医生主观图像质量评分均更高(P0.05),与FBP组比较,FIRST组目标血管颈总动脉(CCA)、颈内动脉(ICA)颈段、椎动脉(VA)、大脑中动脉(MCA)水平段、大脑前动脉(ACA)水平段的SNR值、CNR值均更高,背景噪声值均更低(P<0.05);与FBP组相较,FIRST组的诊断价值更高,其与减影血管造影检查结果一致。结论:在头颈部CTA的扫描过程中,采用FIRST算法重建后的图像质量要优于FBP算法,FIRST算法在相同辐射剂量下提供更高SNR、CNR和更低噪声,能够在一定程度上满足头颈部CTA检查患者的诊断需求。 展开更多
关键词 头颈部CT血管成像 全模型迭代重建算法 滤波反投影算法 图像质量
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Extension of emission expectation maximization lookalike algorithms to Bayesian algorithms 认领 引用 被引量：1
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作者 Gengsheng L.Zeng Ya Li 《Visual Computing for Industry,Biomedicine,and Art》 EI 2019年第1期119-128,共10页
We recently developed a family of image reconstruction algorithms that look like the emission maximum-likelihood expectation-maximization(ML-EM)algorithm.In this study,we extend these algorithms to Bayesian algorithms... We recently developed a family of image reconstruction algorithms that look like the emission maximum-likelihood expectation-maximization(ML-EM)algorithm.In this study,we extend these algorithms to Bayesian algorithms.The family of emission-EM-lookalike algorithms utilizes a multiplicative update scheme.The extension of these algorithms to Bayesian algorithms is achieved by introducing a new simple factor,which contains the Bayesian information.One of the extended algorithms can be applied to emission tomography and another to transmission tomography.Computer simulations are performed and compared with the corresponding un-extended algorithms.The total-variation norm is employed as the Bayesian constraint in the computer simulations.The newly developed algorithms demonstrate a stable performance.A simple Bayesian algorithm can be derived for any noise variance function.The proposed algorithms have properties such as multiplicative updating,non-negativity,faster convergence rates for bright objects,and ease of implementation.Our algorithms are inspired by Green’s one-steplate algorithm.If written in additive-update form,Green’s algorithm has a step size determined by the future image value,which is an undesirable feature that our algorithms do not have. 展开更多
关键词 Image reconstruction Tomography Iterative reconstruction algorithm
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基于压缩感知的快速Bregman地震数据重建方法 认领 引用 被引量：2
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作者 孙小东 李傲伟 +4 位作者 秦宁 蒋润 王敬伊 赵亮 孙耀庭 《中国石油大学学报（自然科学版）》 EI CAS CSCD 北大核心 2025年第4期62-68,共7页
受地面环境、设备及成本等因素的影响,野外采集的地震数据往往存在缺失道,快速有效地重建缺失地震数据十分重要。针对缺失道的地震数据,根据压缩感知理论,提出一种快速Bregman方法的地震数据重建方法,并采用多尺度、多方向曲波变换作为... 受地面环境、设备及成本等因素的影响,野外采集的地震数据往往存在缺失道,快速有效地重建缺失地震数据十分重要。针对缺失道的地震数据,根据压缩感知理论,提出一种快速Bregman方法的地震数据重建方法,并采用多尺度、多方向曲波变换作为稀疏基。通过Bregman方法将求解L1范数问题分解为一系列子问题,引入快速迭代收缩阈值方法(FISTA)高效、准确地求解子问题,从而实现对缺失数据的高质量重构。结果表明,基于压缩感知的快速Bregman方法可以对构造复杂的地震数据进行高效的重建,并且提高迭代计算的重建精度。对于缺失地震数据的重建,所提方法在效率和精度方面均高于LBM和FISTA方法。 展开更多
关键词 地震数据重建 压缩感知 快速Bregman方法 快速迭代收缩阈值 曲波变换
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儿童超低剂量胸部CT检查中应用ASiR-V算法对其辐射剂量及图像质量的影响 认领 引用 被引量：1
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作者 王立敏 吕秀敏 +1 位作者 王艳萍 徐璐璐 《中国辐射卫生》 2025年第4期540-545,共6页
目的探讨儿童超低剂量胸部CT检查中应用多模型自适应统计迭代重建(ASiR-V)算法对辐射剂量、图像质量的影响。方法选择本院72例行胸部CT检查儿童(入院均在2024年1月—2025年1月期间)为研究对象,按数字随机表分为2组,对照组(n=36)管电压为... 目的探讨儿童超低剂量胸部CT检查中应用多模型自适应统计迭代重建(ASiR-V)算法对辐射剂量、图像质量的影响。方法选择本院72例行胸部CT检查儿童(入院均在2024年1月—2025年1月期间)为研究对象,按数字随机表分为2组,对照组(n=36)管电压为100 kVp,采用传统滤波反投影(FBP)算法,观察组(n=36)管电压为80 kVp,分别进行30%ASiR-V(观察1组)、60%ASiR-V(观察2组)、90%ASiR-V(观察3组)重建,记录各组辐射剂量,并对图像质量进行主、客观评价。结果观察组CTDIvol(0.86±0.09)mGy、DLP(25.90±3.55)mGy·cm、ED(0.01±0.001)mSv低于对照组(P<0.05)。4组间图像质量主观评分未见统计学差异(z=-2.206,P=0.530),另经Fisher精确检验显示,观察2组4~5分占比率高于观察3组(P=0.024)。观察组2组、3组纵隔窗升主动脉噪声值以及肺窗右、左中肺、右、左上肺噪声值低于对照组,且3组低于2组(P<0.05)。观察组2组、3组升主动脉SNR、肝脏SNR高于对照组,且3组高于2组(P<0.05)。结论60%ASiR-V算法重建用于儿童超低剂量胸部CT检查,能确保良好图像质量的同时,减少辐射剂量,提高检查安全性。 展开更多
关键词 儿童 多模型自适应统计迭代重建算法 超低剂量 胸部CT 辐射剂量 图像质量
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