MATLAB一些简单的图像处理程序

1

I=imread('pout.tif');figure,imshow(I);[m,n]=size(I);Inew=zeros(floor(m/2),n);for i=1:m    for j=1:n    Inew(i,j)=I(2*i-1,j);    endendfigure,imshow(uint8(Inew))

2

clcclear x=0:255;y1=x;figure,plot(x,y1,'r')hold ony2=255:-1:0;plot(x,y2,'b')ylog=255*(log(x+1)/log(256));plot(x,ylog,'g+')yexp=255*x.^3/255^3;plot(x,yexp,'y+')c=255/255^3;ynthroot=nthroot((x/c),3);plot(x,ynthroot,'yo')

3

I=imread('moon.tif');I=double(I);[m,n]=size(I);for i=1:m    for j=1:n        if I(i,j)<100            Inew(i,j)=3*I(i,j);        elseif I(i,j)>200            Inew(i,j)=0.8*I(i,j);        else            Inew(i,j)=I(i,j);        end    endendfigure,imshow(Inew,[])

4

clearclcI=imread('moon.tif');I=im2double(I);[m,n]=size(I);for i=1:m    for j=1:n        Inew(i,j)=I(i,j)^0.2;    endendfigure,imshow(I,[])figure,imshow(Inew,[])

5

每个像素点的计算与查找表的比较

clearclcI=imread('moon.tif');I=im2double(I);[m,n]=size(I);%循环实现ticfor i=1:m    for j=1:n        Inew(i,j)=255*log(I(i,j)+1)/log(256);    endendtoc%查找表ticx=0:255;c=255/log(256);y=c*log(x+1);I_log=uint8(y(x+1));figure,plot(x,y)tocfigure,imshow(I_log,[])figure,imshow(I,[])figure,imshow(Inew,[])

6

显示一幅图像的直方图

I=imread('pout.tif');figure,imshow(I)[m,n]=size(I);h=zeros(1,256);for k=0:255    for i=1:m        for j=1:n            if(I(i,j)==k)               h(k+1)=h(k+1)+1;            end        end    endendfigure,bar(h)

改进后代码：

I=imread('pout.tif');figure,imshow(I)[m,n]=size(I);h=zeros(1,256);for i=1:m    for j=1:n        h(I(i,j)+1)=h(I(i,j)+1)+1;    endendfigure,bar(h)

将一幅图经直方图均衡化处理

I=imread('pout.tif');figure,imshow(I)[m,n]=size(I);h=zeros(1,256);for i=1:m    for j=1:n        h(I(i,j)+1)=h(I(i,j)+1)+1;    endendfigure,bar(h)p=h/(m*n);sum=0;for i=1:256    sum=sum+p(i);    y(i)=round(sum*255);endfor i=1:m    for j=1:n        Inew(i,j)=y(I(i,j)+1);    endendfigure,imshow(unit8(Inew))

7 邻域处理

I=imread('pout.tif');I=double(I);%卷积模板的不同处理效果不同%M=ones(3,3)/9;将一幅图模糊处理； M=[0 -1 0;-1 5 -1;0 -1 0];将一幅图锐化处理，改变中心位置的值有不同效果%M=[1 1 1;0 0 0;-1 -1 -1];指出原始图像中水平边缘存在位置的图像；M=[1 0 -1;1 0 -1;1 0 -1];指出原始图像中垂直边缘存在位置的图像M=ones(3,3)/9;[m,n]=size(I);Inew=zeros(m,n);%从2开始到m-1忽略边界for i=2:m-1         for j=2:n-1      Inew(i,j)=I(i-1,j-1)*M(1,1)+I(i-1,j)*M(1,2)+...      I(i-1,j+1)*M(1,3)+I(i,j-1)*M(2,1)+I(i,j)*M(2,2)+...      I(i,j+1)*M(2,3)+I(i+1,j-1)*M(3,1)+I(i+1,j)*M(3,2)+...       I(i+1,j+1)*M(3,3);    endendfigure,imshow(uint8(Inew))