matlab图像处理函数总结

1.将图像二值化

I=imread('nan.jpg');

BW=im2bw(I,0.2);//必须在0-1之间

imshow(BW)

2.灰度图像保存文件名必须为.pgm

3.将灰度图像转换为二值图像

I=imread('nan.pgm');

subplot(121);

imshow(I);

title('?-?ò?èí???')

subplot(122);

BW=dither(I);

imshow(BW);

title('×a??oóμ??t?μí???')

4.滑动邻域操作

I=imread('nan.pgm');//格式必须为.pgm，即二值图像f=@(x)max(x(:));

I2=nlfilter(I,[3,3],f);

figure,

subplot(121);imshow(I);subplot(122);imshow(I2);

5.分离块操作

I=imread('nan.pgm');

f=@(x)uint8(round(mean2(x)*ones(size(x))));

I2=blkproc(I,[8,8],f);

figure

subplot(121);imshow(I);subplot(122);imshow(I2);

6.图像插值

I=imread('nan.pgm');

[m,n]=size(I);

x=1:n;y=1:m;[x,y]=meshgrid(x,y);

x1=1:4:n;y1=1:4:m;[x1,y1]=meshgrid(x1,y1);

I1=interp2(x,y,I,x1,y1,'nearest');

figure,

subplot(121),imshow(I);subplot(122),imshow(I1);

7.图像缩放

I=imread('nan.pgm');

[m,n]=size(I);

J1=imresize(I,0.08);

J2=imresize(I,8,'nearest');

J3=imresize(I,[18*m 18*n],'bilinear');

figure,

subplot(221),imshow(I);subplot(222),imshow(J1); subplot(223),imshow(J2);subplot(224),imshow(J3);

8.图像交互式剪裁

I=imread('nan.pgm');

figure,imshow(I)

I0=imcrop;

figure,imshow(I0);

9.图像参数式剪裁

I=imread('nan.pgm');

I2=imcrop(I,[150 160 150 150]); imshow(I),figure,imshow(I2)

10.离散余弦变换

RGB=imread('nannan.jpg');

I=rgb2gray(RGB);

J=dct2(I);

imshow(log(abs(J)),[])

colormap(jet(64)),colorbar figure;

J(abs(J)<10)=0;

K=idct2(J)/50;

imshow(K)

11.余弦变换压缩

I=imread('nan.pgm');

I=im2double(I);

T=dctmtx(8);

B=blkproc(I,[8 8],'P1*x*P2',T,T); mask=[1 1 1 1 1 0 0 0

1 1 1 1 0 0 0 0

1 1 1 0 0 0 0 0

1 1 0 0 0 0 0 0

1 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0

0 0 0 0 0 0 0 0];

B2=blkproc(B,[8 8],'P1.*x',mask);

I2=blkproc(B2,[8 8],'P1*x*P2',T',T); imshow(I)

figure;

imshow(I2)

12.小波变换压缩

I=imread('nan.pgm');

subplot(221);

image(I);

colormap(map)

title('?-ê?í???');

axis square

disp('?1???°í???Xμ?′óD?');

whos('I')

[c,s]=wavedec2(I,2,'bior3.7');

cal=appcoef2(c,s,'bior3.7',1);

ch1=detcoef2('h',c,s,1);

cv1=detcoef2('v',c,s,1);

cd1=detcoef2('d',c,s,1);

a1=wrcoef2('a',c,s,'bior3.7',1);

h1=wrcoef2('h',c,s,'bior3.7',1);

v1=wrcoef2('v',c,s,'bior3.7',1);

d1=wrcoef2('d',c,s,'bior3.7',1);

c1=[a1,h1;v1,d1];

subplot(222);

image(c1);

axis square;

title('·??aoóμí?μoí???μD??￠');

ca1=appcoef2(c,s,'bior3.7',1);

ca1=wcodemat(ca1,440,'mat',0);

ca1=0.5*ca1;

subplot(223);

image(ca1);

colormap(map);

axis square;

title('μúò?′??1??í???');

disp('μúò?′??1??í???μ?′óD??a￡o');

whos('ca1')

ca2=appcoef2(c,s,'bior3.7',2);

ca2=wcodemat(ca2,440,'mat',0);

ca2=0.25*ca2;

subplot(224);

image(ca2);

colormap(map);

axis square;

title('μú?t′??1??í???');

disp('μú?t′??1??í???μ?′óD??a￡o');

whos('ca2')

压缩前图像I的大小

Name Size Bytes Class Attributes

I 539x551 296989 uint8

第一次压缩图像的大小为：

Name Size Bytes Class Attributes ca1 277x283 627128 double

第二次压缩图像的大小为：

Name Size Bytes Class Attributes ca2 146x149 174032 double

13.小波压缩图像

A=imread('mengnan.png');

A=double(A);

Xrgb=0.2990*A(:,:,1)+0.5870*A(:,:,2)+0.1140*A(:,:,3); Nbcolor=255;

X=wcodemat(Xrgb,Nbcolor);

map=pink(Nbcolor);

image(X);

whos('A')

whos('X');

colormap(map);

colorbar;

Name Size Bytes Class Attributes A 901x1201x3 25970424 double Name Size Bytes Class Attributes

X 901x1201 8656808 double

14.图像缩放

A=imread('nannan.jpg');

B=imresize(A,0.5,'nearest');

figure,imshow(A);title('?-í???');

figure,imshow(B);title('í?????·?');

whos('A');

whos('B');

Name Size Bytes Class Attributes A 632x571x3 1082616 uint8 Name Size Bytes Class Attributes

B 316x286x3 271128 uint8