computed tomography 三维图像重建算法，该算法在二维ART基础上改进所得
标签： tomography computed 三维图像 重建算法
上传时间： 2014-01-15
上传用户：jichenxi0730
用于computed tomography 的算法测试计算投影数据的simpson积分函数
标签： tomography computed simpson 算法
上传时间： 2015-06-05
上传用户：dave520l
CT图像金属伪影消除技术的文献。共3篇。 Reduction of Metal Artifacts in X-Ray computed Tomography XrayCT_artifacts Reduction of CT Artifacts Caused by Metallic Implants 由Willi A. Kalender, PhD Robert Hebel, Dipl Phys Johannes Ebersberger, Dr rer nat撰写
标签： XrayCT_artifacts Tomography Reduction Artifacts
上传时间： 2013-12-06
上传用户：脚趾头
computed distribution of the magnetic field Hz within an wvolving 2D dielectric mircopille with initial r=667nm run in COMSOL with Matlab
标签： distribution dielectric mircopille computed
上传时间： 2013-12-09
上传用户：zaizaibang
工业X-CT（X-ray computed Tomography）无损检测技术是以不损伤或者破坏被检测对象的一种高新检测技术，被誉为最佳的无损检测手段，在无损检测领域日益受到人们的青睐。近年来，各国都在投入大量的人力、物力对其进行研究与开发。 目前，工业CT主要采用第二代和第三代扫描方式。在工业CT第三代扫描方式中，扫描系统仅作“旋转”运动，控制系统比较简单。对此，我国已取得了可喜的成绩。然而，对工业CT系统中的二代扫描运动控制系统，即针对“平移+旋转”运动的控制系统的研究，我国已有采用，但与发达国家相比，还存在较大的差距。二代扫描方式与其它扫描方式相比，具有对被检物的尺寸没有要求，且能够对感兴趣的检测区域进行局部扫描的独特优点。同时X光源的射线出束角较小（一般小于20°），因此在工业X-CT系统主要采用二代扫描运动控制。有鉴于此，本论文结合有关科研项目，开展了工业X-CT二代扫描控制系统的研究。 论文首先介绍了工业X-CT系统的工作原理和各种扫描运动控制方式的特点，阐述了开展二代扫描控制的研究目的和意义。其次，根据二代扫描控制的特点，提出了“在优先满足工业X-CT二代扫描控制的基础上，力求实现对工业X-CT扫描运动的通用控制，使其能同时支持一、三代扫描方式”的设计思想。据此，研究确立了基于单片机AT89LV52及FPGA芯片EP1C3T100C8的运动控制架构，以实现二代扫描控制系统的设计方案。论文详细介绍了可编程逻辑器件FPGA的工作原理和开发流程，并对其相关开发环境QuartusII4.1作了阐述。结合运动控制系统的硬件设计，详细介绍了各功能模块的具体设计过程，给出了相关的设计原理框图和实际运行波形。并制作了相应的PCB板，调试了整个硬件控制系统。最后，论文还详细研究了利用VisualC++6.0来完成上位机控制软件的设计，给出了运动控制主界面及扫描运动控制功能软件设计的流程图。 论文对整个运动控制系统采用的经济型的开环控制技术所带来的不利影响，分析研究了增加步进电机的细分数以提高扫描精度的可能性，并对所研究的控制系统在调试过程中出现的一些问题及解决方案作了简要的分析，提出了一些完善方法。
上传时间： 2013-04-24
上传用户：stella2015
function y_cum = cum2x (x,y, maxlag, nsamp, overlap, flag) ％CUM2X Cross-covariance ％ y_cum = cum2x (x,y,maxlag, samp_seg, overlap, flag) ％ x,y - data vectors/matrices with identical dimensions ％ if x,y are matrices, rather than vectors, columns are ％ assumed to correspond to independent realizations, ％ overlap is set to 0, and samp_seg to the row dimension. ％ maxlag - maximum lag to be computed [default = 0] ％ samp_seg - samples per segment [default = data_length] ％ overlap - percentage overlap of segments [default = 0] ％ overlap is clipped to the allowed range of [0,99].
标签： cum2x y_cum Cross-covariance function
上传时间： 2015-09-08
上传用户：xieguodong1234
Each arc of a binary-state network has good/bad states. The system reliability, the probability that source s communicates with sink t, can be computed in terms of minimal paths (MPs). An MP is an ordered sequence of arcs from s to t that has no cycle. Note that a minimal path is different from the so-called minimum path. The latter is a path with minimum cost.
标签： binary-state reliability probability network
上传时间： 2015-12-04
上传用户：xcy122677
Probabilistic Principal Components Analysis. [VAR, U, LAMBDA] = PPCA(X, PPCA_DIM) computes the principal ％ component subspace U of dimension PPCA_DIM using a centred covariance matrix X. The variable VAR contains the off-subspace variance (which is assumed to be spherical), while the vector LAMBDA contains the variances of each of the principal components. This is computed using the eigenvalue and eigenvector decomposition of X.
标签： Probabilistic Components Principal Analysis
上传时间： 2016-04-28
上传用户：qb1993225
OTSU Gray-level image segmentation using Otsu s method. Iseg = OTSU(I,n) computes a segmented image (Iseg) containing n classes by means of Otsu s n-thresholding method (Otsu N, A Threshold Selection Method from Gray-Level Histograms, IEEE Trans. Syst. Man Cybern. 9:62-66 1979). Thresholds are computed to maximize a separability criterion of the resultant classes in gray levels. OTSU(I) is equivalent to OTSU(I,2). By default, n=2 and the corresponding Iseg is therefore a binary image. The pixel values for Iseg are [0 1] if n=2, [0 0.5 1] if n=3, [0 0.333 0.666 1] if n=4, ... [Iseg,sep] = OTSU(I,n) returns the value (sep) of the separability criterion within the range [0 1]. Zero is obtained only with images having less than n gray level, whereas one (optimal value) is obtained only with n-valued images.
标签： OTSU segmentation Gray-level segmented
上传时间： 2017-04-24
上传用户：yuzsu
The frequency domain plays an important role in image processing to smooth, enhance, and detect edges of images. Although image data typically does not include imaginary values, the fast Fourier transform (FFT) has been used for obtaining spectra. In this paper, the fast Hartley transform (FHT) is used to transform two-dimensional image data. Because the Hartley transform is real valued, it does not require complex operations. Both spectra and autocorrelations of two-dimensional ultrasound images of normal and abnormal livers were computed.
标签： processing frequency important enhance
上传时间： 2014-01-08
上传用户：1051290259
