x=-pi:pi/20:pi;%左边界-pi,步长pi/20,右边界pi
y=sin(x)/x;
plot(x,y);%画图
grid on;%显示网格

google绘图
y=sin(x)/x
http://www.google.com.hk/#hl=zh-CN&newwindow=1&safe=strict&site=&source=hp&q=y%3Dsin%28x%29%2Fx&oq=y%3Dsin%28x%29%2Fx&aq=f&aqi=&aql=&gs_l=hp.3...3354l9468l0l9765l10l10l0l0l0l0l0l0ll0l0.frgbld.&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=3c699164da2f212&biw=1366&bih=586

y=ln(x) 自然对数函数
http://www.google.com.hk/search?client=safari&rls=en&q=y=ln(x)&ie=UTF-8&oe=UTF-8

y=log(x) 常用对数函数
http://www.google.com.hk/search?hl=zh-CN&newwindow=1&safe=strict&client=safari&rls=en&q=y%3Dlog%28x%29&oq=y%3Dlog%28x%29&aq=f&aqi=&aql=&gs_l=serp.3...6477l10669l0l10869l14l11l0l0l0l0l0l0ll0l0.frgbld.

y=exp(x) 即y=e^x
http://www.google.com.hk/search?hl=zh-CN&newwindow=1&safe=strict&client=safari&rls=en&biw=1366&bih=651&q=y%3Dexp+%28x%29&oq=y%3Dexp+%28x%29&aq=f&aqi=&aql=&gs_l=serp.3...1460l3262l0l3710l8l7l0l0l0l0l0l0ll0l0.frgbld.

y=7^x 指数函数
http://www.google.com.hk/search?hl=zh-CN&newwindow=1&safe=strict&client=safari&rls=en&biw=1366&bih=651&q=y%3D7%5Ex&oq=y%3D7%5Ex&aq=f&aqi=&aql=&gs_l=serp.3...11309l14855l0l15334l6l6l0l0l0l0l720l720l6-1l1l0.frgbld.

y=x^7 幂函数
http://www.google.com.hk/search?hl=zh-CN&newwindow=1&safe=strict&client=safari&rls=en&biw=1366&bih=651&q=y%3Dx%5E7&oq=y%3Dx%5E7&aq=f&aqi=&aql=&gs_l=serp.3...150730l151940l0l152188l6l5l0l0l0l0l0l0ll0l0.frgbld.

y=1/(2*pi)^(1/2)*exp((-1)*x^2/2) //正态分布
http://www.google.com.hk/#hl=zh-CN&newwindow=1&safe=strict&q=y%3D1%2F%282*pi%29^%281%2F2%29*exp%28%28-1%29*x^2%2F2%29&oq=y%3D1%2F%282*pi%29^%281%2F2%29*exp%28%28-1%29*x^2%2F2%29&aq=f&aqi=&aql=&gs_l=serp.12...25379l225127l12l246622l34l34l0l0l0l0l369l369l3-1l1l0.frgbld.&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=3c699164da2f212&biw=1366&bih=586
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3d曲线画图，使用plot3

>> help plot3PLOT3  Plot lines and points in 3-D space.PLOT3() is a three-dimensional analogue of PLOT().PLOT3(x,y,z), where x, y and z are three vectors of the same length,plots a line in 3-space through the points whose coordinates are theelements of x, y and z.PLOT3(X,Y,Z), where X, Y and Z are three matrices of the same size,plots several lines obtained from the columns of X, Y and Z.Various line types, plot symbols and colors may be obtained withPLOT3(X,Y,Z,s) where s is a 1, 2 or 3 character string made fromthe characters listed under the PLOT command.PLOT3(x1,y1,z1,s1,x2,y2,z2,s2,x3,y3,z3,s3,...) combines the plotsdefined by the (x,y,z,s) fourtuples, where the x's, y's and z's arevectors or matrices and the s's are strings.Example: A helix:t = 0:pi/50:10*pi;plot3(sin(t),cos(t),t);PLOT3 returns a column vector of handles to LINE objects, onehandle per line. The X,Y,Z triples, or X,Y,Z,S quads, can be followed by parameter/value pairs to specify additional properties of the lines.See also PLOT, LINE, AXIS, VIEW, MESH, SURF.

        t = 0:pi/50:10*pi;%定义t区间plot3(sin(t),cos(t),t);%画图，x=sin(t),y=cos(t)

[x,y]=meshgrid(-4:0.2:4,-4:0.2:4);%定义x,y区间,x,y是自变量
z=exp(-0.5*(x.^2+y.^2));%定义z函数关系,exp即e^( )
plot3(x,y,z);%画图xlabel('x');
ylabel('y');
zlabel('z');
title('3d graph');

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3d网格画图

[x,y]=meshgrid(-4:0.2:4,-4:0.2:4);%定义x,y区间
z=exp(-0.5*(x.^2+y.^2));%定义z函数关系
mesh(x,y,z);%画图xlabel('x');
ylabel('y');
zlabel('z');
title('3d graph');

三维表面绘图，将mesh换成surf

http://www.math.uri.edu/~bkaskosz/flashmo/graph3d/
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矩阵

>> A=[1,2,3;4,5,6;7,8,9]//矩阵定义,3行3列A =1     2     34     5     67     8     9>> B=[2:1:10]//也可这样定义B =2     3     4     5     6     7     8     9    10>> eye(2)//2阶单位矩阵ans =1     00     1>> zeros(2)//2阶0矩阵ans =0     00     0>> magic(2)//2阶幻方阵ans =1     34     2>> size(A)//取得矩阵的维数ans =3     3>> A(:,3)//输出矩阵第3列ans =369>> A//输出矩阵A =1     2     34     5     67     8     9>> A(3,:)//输出矩阵第3行ans =7     8     9

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>> help imreadIMREAD Read image from graphics file.A = IMREAD(FILENAME,FMT) reads the image in FILENAME intoA. If the file contains a grayscale intensity image, A isa two-dimensional array.  If the file contains a truecolor(RGB) image, A is a three-dimensional (M-by-N-by-3) array.FILENAME is a string that specifies the name of thegraphics file, and FMT is a string that specifies theformat of the file.  The file must be in the currentdirectory or in a directory on the MATLAB path.  If IMREADcannot find a file named FILENAME, it looks for a filenamed FILENAME.FMT.
....JPEG  Any baseline JPEG image; JPEG images with somecommonly used extensionsTIFF  Any baseline TIFF image, including 1-bit, 8-bit, and24-bit uncompressed images; 1-bit, 8-bit, and 24-bitimages with packbits compression; 1-bit images withCCITT compression; also, 16-bit grayscale, 16-bitindexed, and 48-bit RGB imagesGIF   Any 1-bit to 8-bit GIF imageBMP   1-bit, 4-bit, 8-bit, 16-bit, 24-bit, and 32-bit uncompressedimages; 4-bit and 8-bit run-length encoded (RLE) imagesPNG   Any PNG image, including 1-bit, 2-bit, 4-bit, 8-bit,and 16-bit grayscale images; 8-bit and 16-bitindexed images; 24-bit and 48-bit RGB imagesHDF   8-bit raster image datasets, with or without anassociated colormap; 24-bit raster image datasetsPCX   1-bit, 8-bit, and 24-bit imagesXWD   1-bit and 8-bit ZPixmaps; XYBitmaps; 1-bit XYPixmapsICO   1-bit, 4-bit, and 8-bit uncompressed imagesCUR   1-bit, 4-bit, and 8-bit uncompressed imagesRAS   Any RAS image, including 1-bit bitmap, 8-bit indexed,24-bit truecolor and 32-bit truecolor with alpha.PBM   Any 1-bit PBM image.  Raw (binary) or ASCII (plain) encoded.PGM   Any standard PGM image.  ASCII (plain) encoded witharbitrary color depth.  Raw (binary) encoded with upto 16 bits per gray value.PPM   Any standard PPM image.  ASCII (plain) encoded witharbitrary color depth. Raw (binary) encoded with upto 16 bits per color component.

>> help imwriteIMWRITE Write image to graphics file.IMWRITE(A,FILENAME,FMT) writes the image A to FILENAME.FILENAME is a string that specifies the name of the outputfile, and FMT is a string the specifies the format of thefile.  A can be either a grayscale image (M-by-N) or atruecolor image (M-by-N-by-3).

比如，可以如下进行格式转换

A=imread('lena.jpg');
imwrite(A,'A.bmp');

查看img信息

>> imfinfo('a.bmp')ans = Filename: 'a.bmp'FileModDate: '03-Apr-2012 15:11:10'FileSize: 786486Format: 'bmp'FormatVersion: 'Version 3 (Microsoft Windows 3.x)'Width: 512Height: 512BitDepth: 24ColorType: 'truecolor'FormatSignature: 'BM'NumColormapEntries: 0Colormap: []RedMask: []GreenMask: []BlueMask: []ImageDataOffset: 54BitmapHeaderSize: 40NumPlanes: 1CompressionType: 'none'BitmapSize: 786432HorzResolution: 0VertResolution: 0NumColorsUsed: 0NumImportantColors: 0

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opencv
http://sourceforge.net/projects/opencvlibrary/
http://www.opencv.org.cn/
http://groups.yahoo.com/group/OpenCV/

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halcon
http://www.mvtec.com/halcon/download/
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论坛
http://cvchina.net