小波变换 余弦变换、反变换

RGB=imread('autumn.tif');

A=rgb2gray(RGB);

subplot(3,2,1);imshow(A);

title('原始图像灰度显示');

[cA,cH,cV,cD]=dwt2(A,'db7');

A1=upcoef2('a',cA,'db7',1);

H1=upcoef2('a',cH,'db7',1);

V1=upcoef2('a',cV,'db7',1);

D1=upcoef2('a',cD,'db7',1);

colnb=size(RGB,1);

subplot(3,2,2);

image(wcodemat(cA,colnb));title('近似分量');

subplot(3,2,3);

image(wcodemat(cH,colnb));title('水平细节分量');

subplot(3,2,4);

image(wcodemat(cV,colnb));title('垂直细节分量');

subplot(3,2,5);

image(wcodemat(cD,colnb));title('对角细节分量');

程序运行结果如下：

实验一 DCT变换和IDCT变换

RGB=imread('autumn.tif');

subplot(3,2,1);

imshow(RGB);title('原始图像');

A=rgb2gray(RGB);

subplot(3,2,2);

imshow(A);title('原始图像灰度显示');

B=dct2(A);

subplot(3,2,3);

imshow(log(abs(B)),[ ]),colormap(jet()),colorbartitle('离散余弦变换结果图像');

F=fft2(A);

F2=abs(fftshift(F));

subplot(3,2,4);

imshow((F2),[ ]),colormap(jet()),colorbartitle('傅里叶变换结果图像');

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

K=idct2(B);

subplot(3,2,5);

imshow(K,[0 255]);title('反变换图像');

程序运行结果如下：