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基于DMD空间光调制器解决分层全息成像混叠的研究
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作者 张恒昌 张然 +2 位作者 樊元义 张天宇 褚金奎 《机电工程技术》 2022年第12期24-28,共5页
层析法作为实现三维全息成像的主要方法之一,有着成像计算速度快、效果好的优点,但是传统层析计算得到的像会存在还原像层与层之间混叠的问题,影响成像的质量。为解决使用层析法进行三维全息成像时导致的层间像混叠和串扰的问题,提出了... 层析法作为实现三维全息成像的主要方法之一,有着成像计算速度快、效果好的优点,但是传统层析计算得到的像会存在还原像层与层之间混叠的问题,影响成像的质量。为解决使用层析法进行三维全息成像时导致的层间像混叠和串扰的问题,提出了一种优化方法,基于DMD空间光调制器独特的微镜反射结构,使用球面波为核心模拟全方向均匀衍射,通过计算原始图像分层衍射后的亚振幅全息图,再使用3D-GS算法作为图像质量的优化方法,并对优化结果进行分析,通过仿真实验进行了验证。结果表明提出的方法很好地解决了层析法计算全息三维重建像时层间混叠和串扰的问题,同时,相比于传统分层全息计算,这种方法在短距离衍射成像时具有更大的成像尺寸,并且成像质量有了明显提高。 展开更多
关键词 DMD空间光调制器 层析法 球面波 计算全息
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Least squares twin support vector machine with asymmetric squared loss
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作者 Wu Qing Li Feiyan +2 位作者 zhang hengchang Fan Jiulun Gao Xiaofeng 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2023年第1期1-16,共16页
For classification problems,the traditional least squares twin support vector machine(LSTSVM)generates two nonparallel hyperplanes directly by solving two systems of linear equations instead of a pair of quadratic pro... For classification problems,the traditional least squares twin support vector machine(LSTSVM)generates two nonparallel hyperplanes directly by solving two systems of linear equations instead of a pair of quadratic programming problems(QPPs),which makes LSTSVM much faster than the original TSVM.But the standard LSTSVM adopting quadratic loss measured by the minimal distance is sensitive to noise and unstable to re-sampling.To overcome this problem,the expectile distance is taken into consideration to measure the margin between classes and LSTSVM with asymmetric squared loss(aLSTSVM)is proposed.Compared to the original LSTSVM with the quadratic loss,the proposed aLSTSVM not only has comparable computational accuracy,but also performs good properties such as noise insensitivity,scatter minimization and re-sampling stability.Numerical experiments on synthetic datasets,normally distributed clustered(NDC)datasets and University of California,Irvine(UCI)datasets with different noises confirm the great performance and validity of our proposed algorithm. 展开更多
关键词 classification least SQUARES TWIN support VECTOR machine ASYMMETRIC LOSS noise INSENSITIVITY
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Application of smoothing technique on twin support vector hypersphere
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作者 Wu Qing Gao Xiaofeng +1 位作者 Fan Jiulun zhang hengchang 《The Journal of China Universities of Posts and Telecommunications》 EI CSCD 2020年第3期31-41,共11页
In order to improve the learning speed and reduce computational complexity of twin support vector hypersphere(TSVH),this paper presents a smoothed twin support vector hypersphere(STSVH)based on the smoothing technique... In order to improve the learning speed and reduce computational complexity of twin support vector hypersphere(TSVH),this paper presents a smoothed twin support vector hypersphere(STSVH)based on the smoothing technique.STSVH can generate two hyperspheres with each one covering as many samples as possible from the same class respectively.Additionally,STSVH only solves a pair of unconstraint differentiable quadratic programming problems(QPPs)rather than a pair of constraint dual QPPs which makes STSVH faster than the TSVH.By considering the differentiable characteristics of STSVH,a fast Newton-Armijo algorithm is used for solving STSVH.Numerical experiment results on normally distributed clustered datasets(NDC)as well as University of California Irvine(UCI)data sets indicate that the significant advantages of the proposed STSVH in terms of efficiency and generalization performance. 展开更多
关键词 twin support vector hypersphere Newton-Armijo algorithm smoothing approximation function unconstraint differentiable optimization
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