1.图像反转

MATLAB程序实现如下:
I=imread(\’xian.bmp\’);
J=double(I);
J=-J+(256-1);                 %图像反转线性变换
H=uint8(J);
subplot(1,2,1),imshow(I);
subplot(1,2,2),imshow(H);

2.灰度线性变换
MATLAB程序实现如下:
I=imread(\’xian.bmp\’);
subplot(2,2,1),imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系
I1=rgb2gray(I);
subplot(2,2,2),imshow(I1);
title(\’灰度图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系
J=imadjust(I1,[0.1 0.5],[]); %局部拉伸,把[0.1 0.5]内的灰度拉伸为[0 1]
subplot(2,2,3),imshow(J);
title(\’线性变换图像[0.1 0.5]\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
K=imadjust(I1,[0.3 0.7],[]); %局部拉伸,把[0.3 0.7]内的灰度拉伸为[0 1]
subplot(2,2,4),imshow(K);
title(\’线性变换图像[0.3 0.7]\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

3.非线性变换
MATLAB程序实现如下:
I=imread(\’xian.bmp\’);
I1=rgb2gray(I);
subplot(1,2,1),imshow(I1);
title(\’灰度图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
J=double(I1);
J=40*(log(J+1));
H=uint8(J);
subplot(1,2,2),imshow(H);
title(\’对数变换图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

4.直方图均衡化
MATLAB程序实现如下:
I=imread(\’xian.bmp\’);
I=rgb2gray(I);
figure;
subplot(2,2,1);
imshow(I);
subplot(2,2,2);
imhist(I);
I1=histeq(I);
figure;
subplot(2,2,1);
imshow(I1);
subplot(2,2,2);
imhist(I1);

5.线性平滑滤波器
MATLAB实现领域平均法抑制噪声程序:
I=imread(\’xian.bmp\’);
subplot(231)
imshow(I)
title(\’原始图像\’)
I=rgb2gray(I);
I1=imnoise(I,\’salt & pepper\’,0.02);
subplot(232)
imshow(I1)
title(\’添加椒盐噪声的图像\’)
k1=filter2(fspecial(\’average\’,3),I1)/255;          %进行3*3模板平滑滤波
k2=filter2(fspecial(\’average\’,5),I1)/255;          %进行5*5模板平滑滤波k3=filter2(fspecial(\’average\’,7),I1)/255;          %进行7*7模板平滑滤波
k4=filter2(fspecial(\’average\’,9),I1)/255;          %进行9*9模板平滑滤波
subplot(233),imshow(k1);title(\’3*3模板平滑滤波\’);
subplot(234),imshow(k2);title(\’5*5模板平滑滤波\’);
subplot(235),imshow(k3);title(\’7*7模板平滑滤波\’);
subplot(236),imshow(k4);title(\’9*9模板平滑滤波\’);

6.中值滤波器
MATLAB实现中值滤波程序如下:
I=imread(\’xian.bmp\’);
I=rgb2gray(I);
J=imnoise(I,\’salt&pepper\’,0.02);
subplot(231),imshow(I);title(\’原图像\’);
subplot(232),imshow(J);title(\’添加椒盐噪声图像\’);
k1=medfilt2(J);            %进行3*3模板中值滤波
k2=medfilt2(J,[5,5]);      %进行5*5模板中值滤波
k3=medfilt2(J,[7,7]);      %进行7*7模板中值滤波
k4=medfilt2(J,[9,9]);      %进行9*9模板中值滤波
subplot(233),imshow(k1);title(\’3*3模板中值滤波\’);
subplot(234),imshow(k2);title(\’5*5模板中值滤波\’);
subplot(235),imshow(k3);title(\’7*7模板中值滤波\’);
subplot(236),imshow(k4);title(\’9*9模板中值滤波\’);

7.用Sobel算子和拉普拉斯对图像锐化:
I=imread(\’xian.bmp\’);
subplot(2,2,1),imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I1=im2bw(I);
subplot(2,2,2),imshow(I1);
title(\’二值图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
H=fspecial(\’sobel\’);     %选择sobel算子 
J=filter2(H,I1);            %卷积运算
subplot(2,2,3),imshow(J);
title(\’sobel算子锐化图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
h=[0 1 0,1 -4 1,0 1 0];   %拉普拉斯算子
J1=conv2(I1,h,\’same\’);            %卷积运算
subplot(2,2,4),imshow(J1);
title(\’拉普拉斯算子锐化图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

8.梯度算子检测边缘
MATLAB实现如下:
I=imread(\’xian.bmp\’);
subplot(2,3,1);
imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I1=im2bw(I);
subplot(2,3,2);
imshow(I1);
title(\’二值图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I2=edge(I1,\’roberts\’);
figure;
subplot(2,3,3);
imshow(I2);
title(\’roberts算子分割结果\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I3=edge(I1,\’sobel\’);
subplot(2,3,4);
imshow(I3);
title(\’sobel算子分割结果\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I4=edge(I1,\’Prewitt\’);
subplot(2,3,5);
imshow(I4);
title(\’Prewitt算子分割结果\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

9.LOG算子检测边缘
MATLAB程序实现如下:
I=imread(\’xian.bmp\’);
subplot(2,2,1);
imshow(I);
title(\’原始图像\’);
I1=rgb2gray(I);
subplot(2,2,2);
imshow(I1);
title(\’灰度图像\’);
I2=edge(I1,\’log\’);
subplot(2,2,3);
imshow(I2);
title(\’log算子分割结果\’);

10.Canny算子检测边缘
MATLAB程序实现如下:
I=imread(\’xian.bmp\’);
subplot(2,2,1);
imshow(I);
title(\’原始图像\’)
I1=rgb2gray(I);
subplot(2,2,2);
imshow(I1);
title(\’灰度图像\’);
I2=edge(I1,\’canny\’);
subplot(2,2,3);
imshow(I2);
title(\’canny算子分割结果\’);

11.边界跟踪(bwtraceboundary函数)
clc
clear all
I=imread(\’xian.bmp\’);
figure
imshow(I);
title(\’原始图像\’);
I1=rgb2gray(I);                %将彩色图像转化灰度图像 
threshold=graythresh(I1);        %计算将灰度图像转化为二值图像所需的门限
BW=im2bw(I1, threshold);       %将灰度图像转化为二值图像
figure
imshow(BW);
title(\’二值图像\’);
dim=size(BW);
col=round(dim(2)/2)-90;         %计算起始点列坐标
row=find(BW(:,col),1);          %计算起始点行坐标
connectivity=8;
num_points=180;
contour=bwtraceboundary(BW,[row,col],\’N\’,connectivity,num_points);
%提取边界
figure
imshow(I1);
hold on;
plot(contour(:,2),contour(:,1), \’g\’,\’LineWidth\’ ,2);
title(\’边界跟踪图像\’);

12.Hough变换
I= imread(\’xian.bmp\’);
rotI=rgb2gray(I);
subplot(2,2,1);
imshow(rotI);
title(\’灰度图像\’);
axis([50,250,50,200]);
grid on;                
axis on;
BW=edge(rotI,\’prewitt\’);
subplot(2,2,2);
imshow(BW);
title(\’prewitt算子边缘检测后图像\’);
axis([50,250,50,200]);
grid on;                
axis on;
[H,T,R]=hough(BW);
subplot(2,2,3);
imshow(H,[],\’XData\’,T,\’YData\’,R,\’InitialMagnification\’,\’fit\’);
title(\’霍夫变换图\’);
xlabel(\’\theta\’),ylabel(\’\rho\’);
axis on , axis normal, hold on;
P=houghpeaks(H,5,\’threshold\’,ceil(0.3*max(H(:))));
x=T(P(:,2));y=R(P(:,1));
plot(x,y,\’s\’,\’color\’,\’white\’);
lines=houghlines(BW,T,R,P,\’FillGap\’,5,\’MinLength\’,7);
subplot(2,2,4);,imshow(rotI);
title(\’霍夫变换图像检测\’);
axis([50,250,50,200]);
grid on;                
axis on;
hold on;
max_len=0;
for k=1:length(lines)
xy=[lines(k).point1;lines(k).point2];
plot(xy(:,1),xy(:,2),\’LineWidth\’,2,\’Color\’,\’green\’);
plot(xy(1,1),xy(1,2),\’x\’,\’LineWidth\’,2,\’Color\’,\’yellow\’);
plot(xy(2,1),xy(2,2),\’x\’,\’LineWidth\’,2,\’Color\’,\’red\’);
len=norm(lines(k).point1-lines(k).point2);
if(len>max_len)
max_len=len;
xy_long=xy;
end
end
plot(xy_long(:,1),xy_long(:,2),\’LineWidth\’,2,\’Color\’,\’cyan\’);

13.直方图阈值法
MATLAB实现直方图阈值法:
I=imread(\’xian.bmp\’);
I1=rgb2gray(I);
figure;
subplot(2,2,1);
imshow(I1);
title(\’灰度图像\’)
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
[m,n]=size(I1);                            %测量图像尺寸参数
GP=zeros(1,256);                           %预创建存放灰度出现概率的向量
for k=0:255
     GP(k+1)=length(find(I1==k))/(m*n);    %计算每级灰度出现的概率,将其存入GP中相应位置
end
subplot(2,2,2),bar(0:255,GP,\’g\’)                   %绘制直方图
title(\’灰度直方图\’)
xlabel(\’灰度值\’)
ylabel(\’出现概率\’)
I2=im2bw(I,150/255);  
subplot(2,2,3),imshow(I2);
title(\’阈值150的分割图像\’)
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I3=im2bw(I,200/255);   %
subplot(2,2,4),imshow(I3);
title(\’阈值200的分割图像\’)
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

14. 自动阈值法:Otsu法
MATLAB实现Otsu算法:
clc
clear all
I=imread(\’xian.bmp\’);
subplot(1,2,1),imshow(I);
title(\’原始图像\’)
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
level=graythresh(I);     %确定灰度阈值
BW=im2bw(I,level);
subplot(1,2,2),imshow(BW);
title(\’Otsu法阈值分割图像\’)
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

15.膨胀操作
I=imread(\’xian.bmp\’);          %载入图像
I1=rgb2gray(I);
subplot(1,2,1);
imshow(I1);
title(\’灰度图像\’)     
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
se=strel(\’disk\’,1);          %生成圆形结构元素
I2=imdilate(I1,se);             %用生成的结构元素对图像进行膨胀
subplot(1,2,2);
imshow(I2);
title(\’膨胀后图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

16.腐蚀操作
MATLAB实现腐蚀操作
I=imread(\’xian.bmp\’);          %载入图像
I1=rgb2gray(I);
subplot(1,2,1);
imshow(I1);
title(\’灰度图像\’)     
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
se=strel(\’disk\’,1);       %生成圆形结构元素
I2=imerode(I1,se);        %用生成的结构元素对图像进行腐蚀
subplot(1,2,2);
imshow(I2);
title(\’腐蚀后图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系

17.开启和闭合操作
MATLAB实现开启和闭合操作
I=imread(\’xian.bmp\’);          %载入图像
subplot(2,2,1),imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系 
I1=rgb2gray(I);
subplot(2,2,2),imshow(I1);
title(\’灰度图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系                  
se=strel(\’disk\’,1);     %采用半径为1的圆作为结构元素
I2=imopen(I1,se);         %开启操作
I3=imclose(I1,se);        %闭合操作
subplot(2,2,3),imshow(I2);
title(\’开启运算后图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系
subplot(2,2,4),imshow(I3);
title(\’闭合运算后图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系

18.开启和闭合组合操作
I=imread(\’xian.bmp\’);          %载入图像
subplot(3,2,1),imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系 
I1=rgb2gray(I);
subplot(3,2,2),imshow(I1);
title(\’灰度图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系                  
se=strel(\’disk\’,1);    
I2=imopen(I1,se);         %开启操作
I3=imclose(I1,se);        %闭合操作
subplot(3,2,3),imshow(I2);
title(\’开启运算后图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系
subplot(3,2,4),imshow(I3);
title(\’闭合运算后图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系
se=strel(\’disk\’,1);
I4=imopen(I1,se);
I5=imclose(I4,se);
subplot(3,2,5),imshow(I5);        %开—闭运算图像
title(\’开—闭运算图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系 
I6=imclose(I1,se);
I7=imopen(I6,se);
subplot(3,2,6),imshow(I7);        %闭—开运算图像 
title(\’闭—开运算图像\’);
axis([50,250,50,200]);
axis on;                  %显示坐标系   

19.形态学边界提取
利用MATLAB实现如下:
I=imread(\’xian.bmp\’);          %载入图像
subplot(1,3,1),imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I1=im2bw(I);
subplot(1,3,2),imshow(I1);
title(\’二值化图像\’);
axis([50,250,50,200]);
grid on;                  %显示网格线
axis on;                  %显示坐标系
I2=bwperim(I1);                 %获取区域的周长
subplot(1,3,3),imshow(I2);
title(\’边界周长的二值图像\’);
axis([50,250,50,200]);
grid on;
axis on;              

20.形态学骨架提取
利用MATLAB实现如下:
I=imread(\’xian.bmp\’);
subplot(2,2,1),imshow(I);
title(\’原始图像\’);
axis([50,250,50,200]);
axis on;                 
I1=im2bw(I);
subplot(2,2,2),imshow(I1);
title(\’二值图像\’);
axis([50,250,50,200]);
axis on;                
I2=bwmorph(I1,\’skel\’,1);
subplot(2,2,3),imshow(I2);
title(\’1次骨架提取\’);
axis([50,250,50,200]);
axis on;                 
I3=bwmorph(I1,\’skel\’,2);
subplot(2,2,4),imshow(I3);
title(\’2次骨架提取\’);
axis([50,250,50,200]);
axis on;               

21.直接提取四个顶点坐标

 I = imread(\’xian.bmp\’);

I = I(:,:,1); BW=im2bw(I);

figure imshow(~BW)

[x,y]=getpts

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