利用MATLAB实现医学图像处理与分析
利用MATLAB实现医学图像处理与分析边缘是图像最基本的特征。所谓边缘是指图像周围像素灰度有阶跃变化或屋顶状变化的像素的集合, 它存在于目标与背景、目标与目标、区域与区域、基元与基元之间。边缘具有方向和幅度两个特征, 沿边缘走向, 像素值变化比较平缓; 垂直于边缘走向, 像素值变化比较剧烈, 可能呈现阶跃状, 也可能呈现斜坡状因此, 边缘可以分为两种: 一种为阶跃性边缘, 它两边的像素灰度值有着明显的不同; 另一种为屋顶状边缘, 它位于灰度值从增加到减少的变化转折点。对于阶跃性边缘, 二阶方向导数在边缘处呈零交叉; 而对于屋顶状边缘, 二阶方向导数在边缘处取极值。第6期高向军,等:利用 MATLAB实现医学图像处理与分析1749d imw rie( modif, ank le_new series d en, n b)在 MATLA B中,笔者实现算法如下:a读入图像,预定义3.2 Levelset图像分割初始轮廓,如图3(a)所示;b定义离散化水平集函数;c)曲线在医学图像分割研究中,基于 level set技术的活动轮廓模演化,递准过程;d)求解演化后的零水平集,即为分割图像的型正引人注目。本实例在 MATLAB环境中,实现了Chm和边缘,如图3(b)所示。Ⅴese提出的无梯度的活动轮廓模型,并应用在医学图像分割之中。4结束语CⅤ分割方法的基本原理如下:没定义域为Ω的图像uo实践证明,MAT^AB软件功能强大、数据计算能力突出、被闭合边界C划分为目标O(C的内部)和背景B(C的外语言简洁易读。使用图像工具箱中的医学图像处理函数可以部)两个同质区域。两个区域的平均灰度分别为c1和c2此时方便快捷地实现医学图像的读写及简单处理功能。本文用实能量函数可看做为外部能量和内部能量之和,即例证明了在 MATLAB环境中可以方便、快速、有效地实现复杂E(cIc> C)=EinsidefC)+Eoutsidec)医学图像处理算法。同时Ⅵ ATLAR工具箱涉及的专业领域广H, m isc,(uo-Ci2dx dy+泛且功能強大。由于工具箱具有可靠性和开放性,可以方便H2IJout ie c)(o-C2)2dedy-YICI地直接加以使用,也可以将自己的代码加到工具箱中以改进函数功能。因比,在Ⅵ ATLA B(R2006b)环境下,实现医学图像的处理和分析具有很大的应用优势和价值。参考文献:1」田捷,包尚联,周明全.医学影像处理与分析[Ⅵ].北京:电子工业出版社,2003.(a)初始图像(b)分割结果「2]张尢赛,陈福民·D)IαM医学图像窗口变换的加速算法[J.计图3 Level set分割结果算机工程与应用,200339(13):218-2203]王立功,刘伟强,于甬华,等.DCOM医学图像文件格犬解析与当闭合边界C处于两个同质区域的边界时,能量达到最应用研究[J计算机工程与应用,20642(29):210212225小。为了解决曲线的拓扑变化问题,C-V分割法采用了水平[41曾筝,董芳华,陈咣,等.利用 MATLAB实现C断层图像的三维集方法,将闭合边界C嵌入高一维的曲面ψ中,根据初始闭合重建[J·CT理论与应用研究,200413(2):24-29曲线c构造一个内正外负的符号距离水平集函数中这样就5l任忠宝,李佳·基于 MATLA B的颅面三维重构技术J·计算机将关于闭合曲线C的能量函数转换为关于曲面中的能量函(6]王家文,李迎军.MAAB7.0图形图像处理(M].北京:国防数,再通过变分技术可以得到关于曲面的偏微分方程模型,即工业出版社,2006冲=1中/Yd(y中/1中1)-1(mo-c12+2(no-c2)2通(71HANT, VESE L. A ctive con bou rs w ithou t edges JI. EEE Tans过求由面的零水平集就可以得到C的位置mage Process 2001, 10(2): 266 277(上接第1740页)相比,本文算法虽然计算量有所增大,但能acam pos itc m ethod[ J]. Pattern Recogn tion 1982, 22(4: 381正确区分质量中等区域和质量较差的区域,并将背景区域和质385.量较差、后继算法无法恢复的噪声区域分割,保留质量巾等41 MEHTRE B M. F ngerp rmt m age ana ls s for autm atic ren tifica tion区域,使后续算法的处理区域更精确。I J] M achine Vis ion and App lica tons 1993, 6(2-3): 124-1395]苏彦华·Ⅴ balc++数字图像识別技术典型業例[M]·北京:人4结束语民邮电出版社,2004I6]耿茵茵,唐良瑞.指纹图像分级分割算法ⅠJ.北方工业大学学本文提出了一种改进的基于指纹灰度特性的指纹图像分200012(3):2-26割算法,克服了传统自适应阈值分割算法在指纹与背景交接区[7]甘树坤,欧宗瑛,魏鸿磊,基于灰度特性的指纹图像分割算法[J域,以及指纹内部脊线太淡或脊线粘连的区域分割不准及分割古林化工学院学报,200623(1):68-71前景边界的方坎效应问题,适用于更多类型的指纹图像,且分[8] ROSENFILD A, KAK A C. Digita I im age process ing[M].Naw割比较精确。实验结果表明,该算法的分割效果很好,对前景Yor a cadem i press 1976区和背景区的分割更加灵活准确,有效降低了指纹图像噪声的[9]G0 NAZALES R C. WOODSR E. D igital m age processing[M I影响,它不仅能分割出指纹质量较好的图像,也能有效地分割Read a add ison w esley 1992噪声干扰较大的指纹图像,经过分割后的图像指纹纹线清晰、「11田捷,杨鑫,生物特征识别技术理论与应用M],北京:子工业出版社,2005流畅,具有较强的适应性和很高的实用价值。目前该算法已被应用到成熟的指纹识别算法中。10]吴|金,朱兆达图像处理中阂值选取方法3年(192-1992)的进展(12)[J.数据采集与处狸19938(3):1920}(4):26278.参考文執I 12 BAZEN AM, GEREZ S H. Segn en tation of fingeprin t m ages[ c]//l]陆颍.指纹自动识别原理与方法综述[J]·工栏数学学报.2004Prme of the 12th Annual W orks op on C icu its Sys kms and Sign al21(6):10031010Pocess ng Neherland I s n, 2001 276-2802]硎 HANG J anwei I Heng li s udy on segm ent a lgorithm in au m a[l3]冯星奎,颜祖泉,肖兴明,等.指纹图像合成分割法[J.计算机l i fige prill ilen Lifica lion[ J. M cro oomputer Applica tons应用研究,200017(1):7G77199915(12)202214]韩思奇,王蕾·图像分割的阈值法综述丨J].系统工程与皃子技13 CMEBTREUM.C是是出m出是 lishing630 bihgts-ycscrved.htp/w. cnkinct
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系统辨识大牛Ljung编写的MATLAB系统辨识使用手册
系统辨识大牛Ljung编写的MATLAB系统辨识使用手册,这本书详细地介绍了在MATLAB已经所属simulink环境下,系统辨识工具箱的一些使用办法,是一本非常经典的教材!Revision Historypril 1988First printingJuly 1991Second printingMay1995Third printingNovember 2000 Fourth printingRevised for Version 5.0(Release 12)pril 2001Fifth printingJuly 2002Online onlyRevised for Version 5.0.2 Release 13)June 2004Sixth printingRevised for Version 6.0.1(Release 14)March 2005Online onlyRevised for Version 6.1.1Release 14SP2)September 2005 Seventh printingRevised for Version 6.1.2(Release 14SP3)March 2006Online onlyRevised for Version 6.1.3(Release 2006a)September 2006 Online onlyRevised for Version 6.2 Release 2006b)March 2007Online onlyRevised for Version 7.0 ( Release 2007a)September 2007 Online onlyRevised for Version 7.1 (Release 2007bMarch 2008Online onlyRevised for Version 7.2(Release 2008a)October 2008Online onlyRevised for Version 7.2.1 Release 2008b)March 2009Online onlyRevised for Version 7.3(Release 2009a)September 2009 Online onlyRevised for Version 7.3.1(Release 2009b)March 2010Online onlyRevised for Version 7. 4 (Release 2010a)eptember2010 Online onlyRevised for Version 7.4.1(Release 2010b)pril 2011Online onlRevised for Version 7.4.2(Release 2011a)September 2011 Online onlyRevised for Version 7.4.3(Release 2011b)March 2012Online onlyRevised for Version 8.0( Release 2012aabout the DevelopersAbout the Developersystem Identification Toolbox software is developed in association with thefollowing leading researchers in the system identification fieldLennart Ljung. Professor Lennart Ljung is with the department ofElectrical Engineering at Linkoping University in Sweden. He is a recognizedleader in system identification and has published numerous papers and booksin this areaQinghua Zhang. Dr. Qinghua Zhang is a researcher at Institut Nationalde recherche en Informatique et en Automatique(INria) and at Institut deRecherche en Informatique et systemes Aleatoires (Irisa), both in rennesFrance. He conducts research in the areas of nonlinear system identificationfault diagnosis, and signal processing with applications in the fields of energyautomotive, and biomedical systemsPeter Lindskog. Dr. Peter Lindskog is employed by nira dynamiAB, Sweden. He conducts research in the areas of system identificationsignal processing, and automatic control with a focus on vehicle industryapplicationsAnatoli Juditsky. Professor Anatoli Juditsky is with the laboratoire JeanKuntzmann at the Universite Joseph Fourier, Grenoble, france. He conductsresearch in the areas of nonparametric statistics, system identification, andstochastic optimizationAbout the developersContentsChoosing Your System Identification ApproachLinear model structures1-2What Are Model objects?Model objects represent linear systemsAbout model data1-5Types of Model objectsDynamic System Models1-9Numeric Models1-11umeric Linear Time Invariant (LTD Models1-11Identified LTI modelsIdentified Nonlinear models1-12Nonlinear model structures1-13Recommended Model Estimation Sequence1-14Supported Models for Time- and Frequency-DomainData,,,,,,,1-16Supported Models for Time-Domain Data1-16Supported Models for Frequency-Domain Data1-17See also1-18Supported Continuous-and Discrete-Time Models1-19Model estimation commands1-21Creating Model Structures at the command Line ... 1-22about system Identification Toolbox Model Objects ... 1-22When to Construct a Model Structure Independently ofEstimation1-23Commands for Constructing Model Structures1-24Model Properties1-25See als1-27Modeling Multiple-Output Systems ......... 1-28About Modeling multiple-Output Systems1-28Modeling Multiple Outputs Directly1-29Modeling multiple outputs as a Combination ofSingle-Output Models.......1-29Improving Multiple-Output Estimation Results byWeighing Outputs During Estimation ....... 1-30Identified linear Time-Invariant models1-32IDLTI Models1-32Configuration of the Structure of Measured and Noise oRepresentation of the Measured and noise Components foVarious model Types1-33Components ....1-35Imposing Constraints on the Values of ModeParameters1-37Estimation of Linear models1-8Data Import and Processing2「Supported Data ...2-3Ways to Obtain Identification DataWays to Prepare Data for System Identification ... 2-6Requirements on Data SamplingRepresenting Data in MATLAB Workspace·····Time-Domain Data Representation2-9Time-Series Data Representation2-10ContentsFrequency-Domain Data Representation ....... 2-11Importing Data into the Gui2-17Types of Data You Can import into the GUi2-17Importing time-Domain Data into the GUI2-18Importing Frequency-Domain Data into the GUI2-22Importing Data Objects into the GUI ......... 2-30Specifying the data sampling interval2-34Specifying estimation and validation Data2-35Preping data Using Quick StartCreating Data Sets from a Subset of Signal Channelo2-362-37Creating multiexperiment Data Sets in the gUi2-39Managing data in the gui ............. 2-46Representing Time- and Frequency-Domain Data Usingiddata object2-55iddata constructor2-55iddata Properties.........2-58Creating Multiexperiment Data at the Command Line .. 2-61Select Data Channels, I/O Data and Experiments in iddataObjects2-63Increasing Number of Channels or Data Points of iddataObjects2-67Managing iddata Objects2-69Representing Frequency-Response Data Using idfrdObiec2-76idfrd Constructor2-76idfrd Properties2-77Select I/o Channels and Data in idfrd Objects ..... 2-79Adding Input or Output Channels in idfrd Objects2-80Managing idfrd Objects2-83Operations That Create idfrd Objects2-83Analyzing Data quality2-85Is your data ready for modeling?2-85Plotting Data in the guI Versus at the command line2-86How to plot data in the gui2-86How to plot data at the command line2-92How to Analyze Data Using the advice Command2-94Selecting Subsets of Data2-96IXWhy Select Subsets of Data?2-96Extract Subsets of Data Using the GUI2-97Extract Subsets of data at the Command Line2-99Handling Missing Data and outliers2-100Handling missing data2-100Handling outliers2-101Extract and Model Specific Data Segments2-102See also2-103Handling offsets and Trends in Data2-104When to detrend data2-104Alternatives for Detrending Data in GUi or at theCommand-Line2-105Next Steps After detrending2-107How to Detrend Data Using the Gui2-108How to detrend data at the Command line2-109Detrending Steady-State Dat109cending transient Dat2-109See also2-110Resampling Data2-111What Is resampling?...,,.,,,,,,,,,,,.2-111Resampling data without Aliasing Effects2-112See also2-116Resampling data Using the GUi.,,,,2-117Resampling Data at the Command line2-118Filtering Data2-120Supported Filters2-120Choosing to Prefilter Your Data2-120See also2-121How to Filter Data Using the gui2-122Filtering Time-Domain Data in the GuI........ 2-122Content
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