彩色图像转灰度图像

彩色图像转灰度图像

L=imread('i:\1.jpg')

L=double(L);

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

X=wcodemat(Xrgb,NbColors);

map1=gray(NbColors);

image(X);

colormap(map1);

title('原图像的灰度图');

小波压缩-低频信息保留压缩方式

L=imread('i:\1.jpg')

L=double(L);

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

X=wcodemat(Xrgb,NbColors);

map1=gray(NbColors);

image(X);

colormap(map1);

title('原图像的灰度图');

axis square;

disp('灰度图像X的大小');

whos('X')

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

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

ch1=detcoef2('h',c,s,1);%水平方向

cv1=detcoef2('v',c,s,1);%垂直方向

cd1=detcoef2('d',c,s,1);%斜线方向

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);%各频率成分重构c1=[a1,h1;v1,d1];

image(c1);

colormap(gray);

axis square;

title('分解后低频和高频信息');

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

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

ca1=0.5*ca1;

disp('第一次压缩后图像的大小为：');

image(ca1);

colormap(gray);

%colormap(map);

axis square;

title('第一次压缩图像');

whos('ca1')

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

ca2=0.25*ca2;

image(ca2);

colormap(gray);

%colormap(map);

axis square;

title('第二次压缩图像');

disp('第二次压缩后图像大小为：');

whos('ca2')

灰度图像X 的大小

Name Size Bytes Class

X 150x125 150000 double array

Grand total is 18750 elements using 150000 bytes

第一次压缩后图像的大小为：

Name Size Bytes Class

ca1 82x70 45920 double array Grand total is 5740 elements using 45920 bytes

第二次压缩后图像大小为：

Name Size Bytes Class

ca2 48x42 16128 double array Grand total is 2016 elements using 16128 bytes

二维小波压缩

H=imread('i:\1.jpg')

H=double(H);

Grgb=0.2990*H(:,:,1)+0.5870*H(:,:,2)+0.1140*H(:,:,3); NbColors=255;

G=wcodemat(Grgb,NbColors);

map2=gray(NbColors);

figure(4);

image(G);

colormap(map2);

title('原图像的灰度图');

%转换成为灰度级索引图像

[CA1,CH1,CV1,CD1]=dwt2(G,'bior3.7');

%从分解系数中提取近似和细节

[CA1,CH1,CV1,CD1]=dwt2(G,'bior3.7');

A1=upcoef2('a',CA1,'bior3.7',1);

H1=upcoef2('h',CH1,'bior3.7',1);

V1=upcoef2('v',CV1,'bior3.7',1);

D1=upcoef2('d',CD1,'bior3.7',1);

%显示近似和细节

%figure (' name ','近似分量A1');

colormap(map2);

subplot(2,2,1);

image(wcodemat(A1,192));

title('近似A1');

subplot(2,2,2);

image(wcodemat(H1,192));

title('水平细节H1');

subplot(2,2,3);

image(wcodemat(V1,192));

title('垂直细节V1');