Matlab画图入门

转载：http://blog.csdn.net/hustspy1990/article/details/4648761

1.基本画图

程序如下：

x=0:pi/1000:2*pi;y1=sin(2*x);y2=2*cos(2*x);%输出图像plot(x,y1,'k-',x,y2,'b--');title(' Plot of f(x)=sin(2x) and its derivative');%设置X坐标和Y坐标的标签xlabel('x');ylabel('y');%制作图例legend('f(x)=sin(2x)','d/dx f(x)')%显示网格grid on;

显示结果：

 

2.利用有限个点画出平滑曲线

x=1:1:10;y=[1,4,8,10,11,11.5,12,7,5,1];xx=1:0.01:10;%使用了函数interp1yy=interp1(x,y,xx,'cublic');plot(xx,yy,x,y,'.');grid on; 

3.绘制三维曲线

t=0:pi/100:20*pi;x=sin(t);y=cos(t);z=t.*sin(t).*cos(t);plot3(x,y,z);title('Line in 3-D Space');xlabel('X');ylabel('Y');zlabel('Z');grid on;

4.绘制三维曲面

[x,y]=meshgrid(-8:0.5:8);z=sin(sqrt(x.^2+y.^2))./sqrt(x.^2+y.^2+eps);subplot(2,2,1);mesh(x,y,z);title('mesh(x,y,z)')subplot(2,2,2);meshc(x,y,z);title('meshc(x,y,z)')subplot(2,2,3);meshz(x,y,z)title('meshz(x,y,z)')subplot(2,2,4);surf(x,y,z);title('surf(x,y,z)')

标准三维曲面：

t=0:pi/20:2*pi;[x,y,z]= cylinder(2+sin(t),30);subplot(2,2,1);surf(x,y,z);subplot(2,2,2);[x,y,z]=sphere;surf(x,y,z);subplot(2,1,2);[x,y,z]=peaks(30); surf(x,y,z);

其他函数：

subplot(2,2,1);bar3(magic(4))subplot(2,2,2);y=2*sin(0:pi/10:2*pi);stem3(y);subplot(2,2,3);pie3([2347,1827,2043,3025]);subplot(2,2,4);fill3(rand(3,5),rand(3,5),rand(3,5), 'y' )

绘制多峰函数的瀑布图和等高线图：

subplot(1,2,1);[X,Y,Z]=peaks(30);waterfall(X,Y,Z)xlabel('X-axis'),ylabel('Y-axis'),zlabel('Z-axis');subplot(1,2,2);contour3(X,Y,Z,12,'k'); %其中12代表高度的等级数xlabel('X-axis'),ylabel('Y-axis'),zlabel('Z-axis');

5.图形修饰处理

三种图像着色方式效果显示：

[x,y,z]=sphere(20);colormap(copper);subplot(1,3,1);surf(x,y,z);axis equalsubplot(1,3,2);surf(x,y,z);shading flat;axis equalsubplot(1,3,3);surf(x,y,z);shading interp;axis equal

光照处理后的球面：

[x,y,z]=sphere(20);subplot(1,2,1);surf(x,y,z);axis equal;light('Posi',[0,1,1]);shading interp;hold on;plot3(0,1,1,'p');text(0,1,1,' light');subplot(1,2,2);surf(x,y,z);axis equal;light('Posi',[1,0,1]);shading interp;hold on;plot3(1,0,1,'p');text(1,0,1,' light');

图形的裁剪处理：

[x,y]=meshgrid(-5:0.1:5);z=cos(x).*cos(y).*exp(-sqrt(x.^2+y.^2)/4);subplot(1,2,1);surf(x,y,z);shading interp;title('裁剪之前');i=find(x<=0&y<=0);z1=z;z1(i)=NaN;subplot(1,2,2);surf(x,y,z1);shading interp;title('裁剪之后');

从文件载入图像：

[x,cmap]=imread('flower.jpg'); %读取图像的数据阵和色图阵image(x);colormap(cmap);axis image off %保持宽高比并取消坐标轴

制作动画：

[X,Y,Z]=peaks(30); surf(X,Y,Z)axis([-3,3,-3,3,-10,10])axis off;shading interp;colormap(hot);m=moviein(20); %建立一个20列大矩阵for i=1:20view(-37.5+24*(i-1),30) %改变视点m(:,i)=getframe; %将图形保存到m矩阵end movie(m,2); %播放画面2次