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941.
942.
Fan Zhang Author Vitae Author Vitae 《Pattern recognition》2010,43(4):1590-1606
This paper develops new geometrical filtering and edge detection algorithms for processing non-Euclidean image data. We view image data as residing on a Riemannian manifold, and we work with a representation based on the exponential map for this manifold together with the Riemannian weighted mean of image data. We show how the weighted mean can be efficiently computed using Newton's method, which converges faster than the gradient descent method described elsewhere in the literature. Based on geodesic distances and the exponential map, we extend the classical median filter and the Perona-Malik anisotropic diffusion technique to smooth non-Euclidean image data. We then propose an anisotropic Gaussian kernel for image filtering, and we also show how both the median filter and the anisotropic Gaussian filter can be combined to develop a new edge preserving filter, which is effective at removing both Gaussian noise and impulse noise. By using the intrinsic metric of the feature manifold, we also generalise Di Zenzo's structure tensor to non-Euclidean images for edge detection. We demonstrate the applications of our Riemannian filtering and edge detection algorithms both on directional and tensor-valued images. 相似文献
943.
通过介绍μC/OS-Ⅱ实时操作系统中的任务延时功能,分析了系统中的任务延时的优缺点.针对任务延时占用处理器时间与任务总数有关和扫描各个任务占用大量处理器时间的问题,对操作系统中的任务延时机制进行改进.改进后的操作系统在基于第二代Cortex-M3内核的LPC1768处理器上测试,通过软件仿真,得出此方法可以提高系统的实... 相似文献
944.
On improved calibration method for the catadioptric omnidirectional vision with a single viewpoint 总被引:1,自引:0,他引:1
The single viewpoint constraint is a principal optical characteristic for most catadioptric omnidirectional vision. Single
viewpoint catadioptric omnidirectional vision is very useful because it allows the generation of geometrically correct perspective
images from one omnidirectional image. Therefore precise calibration for single viewpoint constraint is needed during system
assembling. However, in most image detection based calibration methods, the nonlinear optical distortion brought by lens is
often neglected. Hence the calibration precision is poor. In this paper, a new calibration method of single viewpoint constraint
for the catadioptric omni-directional vision is proposed. Firstly, an image correction algorithm is obtained by training a
neural network. Then, according to characteristics of the space circular perspective projection, the corrected image of the
mirror boundary is used to estimate its position and attitude relative to the camera to guide the calibration. Since the estimate
is conducted based on actual imaging model rather than the simplified model, the estimate error is largely reduced, and the
calibration accuracy is significantly improved. Experiments are conducted on simulated images and real images to show the
accuracy and the effectiveness of the proposed method. 相似文献
945.
Zhenxiao Gao Tianyuan Xiao Wenhui Fan 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2011,15(3):581-594
Nonlinear optimization algorithms could be divided into local exploitation methods such as Nelder–Mead (NM) algorithm and
global exploration ones, such as differential evolution (DE). The former searches fast yet could be easily trapped by local
optimum, whereas the latter possesses better convergence quality. This paper proposes hybrid differential evolution and NM
algorithm with re-optimization, called as DE-NMR. At first a modified NM, called NMR is presented. It re-optimizes from the
optimum point at the first time and thus being able to jump out of local optimum, exhibits better properties than NM. Then,
NMR is combined with DE. To deal with equal constraints, adaptive penalty function method is adopted in DE-NMR, which relaxes
equal constraints into unequal constrained functions with an adaptive relaxation parameter that varies with iteration. Benchmark
optimization problems as well as engineering design problems are used to experiment the performance of DE-NMR, with the number
of function evaluation times being employed as the main index of measuring convergence speed, and objective function values
as the main index of optimum’s quality. Non-parametric tests are employed in comparing results with other global optimization
algorithms. Results illustrate the fast convergence speed of DE-NMR. 相似文献
946.
In this paper, we present a novel rendezvous algorithm framework ‐ the combination framework, which is named after the term convex combination in computational geometry. The convergence of the proposed algorithms is proved based on the novel tools from the recent results in graph theory and consensus study. It has been observed that the circumcenter algorithm can be considered as a special case of the combination framework. Moreover, the relevant analysis provides us a novel viewpoint on designing and the rendezvous rate of rendezvous algorithms for networked multi‐agent systems with limited sensing ranges. Copyright © 2010 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society 相似文献
947.
实时系统由于其业务对时间要求的特殊性,使得传统工作流技术难以满足其需求.在传统工作流的基础上,针对实时系统提出了实时工作流的概念,并建立了实时工作流元模型.与传统的工作流相比,主要对工作流的时间约束和异常处理进行了考虑.在活动上扩展了启动时间和执行时间,在工作流过程上扩展了执行时间,在并发活动上扩展了并发时间约束等,此外,元模型中还考虑了活动的超时异常以及应用程序和活动之间的执行关系.为了能够利用实时工作流元模型进行实时工作流建模,通过扩展UML定义了一种实时工作流描述语言,并分别从设计要求、定义技术和profile三个方面对实时工作流描述语言进行了阐述,给出了实时工作流的建模规则.最后结合船舶指控系统的具体实例,对建模方法进行了说明. 相似文献
948.
一种新型监狱使用的物联网节点设计 总被引:1,自引:0,他引:1
一种新型智能手铐作为物联网的节点,其主要利用指纹和电子滚码通过优先级进行开关锁来加强安全性,并且通过上位机能够实时地监控手铐的开关状态;同时加上了GPS定位功能,由上位机监控节点所在的位置和移动轨迹,并且系统每小时做一次监测结果备份,监察员可以调用任意时间段的数据.这种新型手铐运用物联网技术便于对犯人进行统一管理和监控,减轻了监狱监控管理人员的负担,并且在犯人逃跑过程中可以起到有效跟踪追捕功能.主要介绍了系统的整体架构、软硬件设计技术和系统功能. 相似文献
949.
950.
实时、准确的交通流量预测是智能交通系统发展的关键.AOSVR是一种支持向量机的在线更新算法,具有模型在线学习的特点,可应用于交通流量的实时预测,其中模型参数的选择是预测性能的关键因素.利用大连SCOOT系统采集的实时数据,通过训练集求解AOSVR的不敏感损失系数ε和惩罚参数C,形成自适应参数选择的AOSVR方法.仿真结果表明该方法能够满足动态路网交通流量预测的实时性和精确性需求,具有一定的应用价值. 相似文献