图像处理之小波变换

Matlab 小波变换

lean图像的行列应该满足2的幂次方

img  =  imread('lena.jpg');

img =rgb2gray(img);

img = double(img);



[ca1 ch1,cv1,cd1] = dwt2(img,'haar');

figure;

imshow([uint8(ca1),uint8(ch1);uint8(cv1),uint8(cd1)]);

title('first wavelet decomposition');



[ca2 ch2,cv2,cd2] = dwt2(ca1,'haar');

figure;

imshow([uint8(ca2),uint8(ch2);uint8(cv2),uint8(cd2)]);

title('second wavelet decomposition');



% restruct img

img_ca1 =  idwt2(ca2,ch2,cv2,cd2,'haar');

img_re = idwt2(img_ca1,ch1,cv1,cd1,'haar');

figure;

imshow( uint8(img_re));

title('wavelet restruct');

参考：

http://media.cs.tsinghua.edu.cn/~ahz/digitalimageprocess/chapter12/chapt12_ahz.htm