搜索
%软阈值硬阈值半软阈值巴特沃斯滤波clccloseallclearallmap=gray(256);x=imread('hzw.jpg');x=rgb2gray(x);subplot(2,3,1);image(x);colormap(map);title('原始图片');axissquare;init=2055615866;randn('seed',init);x1=50.*randn(size(x));%均值为0方差50^2x=double(x)nx=x+x1;subplot(2,3,2);image(nx);colormap(map);title('加噪后的图片');axissquare;c=num2str(c);text(100,100,'PSNR:');text(300,100,c);%硬阈值[thr,sorh,keepapp]=ddencmp('den','wv',nx);nx1=wdencmp('gbl',nx,'sym5',2,thr,'h',keepapp);subplot(2,3,3);image(nx1);title('Ó²ãÐֵȥÔëºóͼÏñ');axissquare;a1=psnr(nx1,x);a1=num2str(a1);text(100,100,'PSNR:');text(300,100,a1);%软阈值nx2=wdencmp('gbl',nx,'sym5',2,thr,'s',keepapp);subplot(2,3,4);image(nx2);title('ÈíãÐֵȥÔëºóͼÏñ');axissquare;c=psnr(nx2,x);c=num2str(c);text(100,100,'PSNR:');text(300,100,c);%半软阈值nx3=hsoft(nx,'sym5',2,0.5,thr);subplot(2,3,5);image(nx3);title('°ëÈíãÐֵȥÔëºóͼƬ');axissquare;a4=psnr(nx3,x);a4=num2str(a4);text(100,100,'PSNR:');text(300,100,a4);%巴特沃斯g=fft2(nx);g=fftshift(g);[m,n]=size(g);N=3;d0=60;n1=floor(m/2);n2=floor(n/2);fori=1:mforj=1:nd=sqrt((i-n1)^2+(j-n2)^2);h=1/(1+(d/d0)^(2*N));g(i,j)=h*g(i,j);endendg=ifftshift(g);g=(real(ifft2(g)));subplot(2,3,6);image(g);title('°ÍÌØÎÖ˹µÍͨÂ˲¨');axissquare;a5=psnr(g,x);a5=num2str(a5);text(100,100,'PSNR:');text(300,100,a5);functionX=hsoft(x,wname,n,thr,thrl)[C,S]=wavedec2(x,n,wname);dcoef=C(prod(S(1,:))+1:end);ind=find(abs(dcoef)thrl)+prod(S(1,:));C(ind)=0;ind=find(abs(dcoef)=thrl&abs(dcoef)thr)+prod(S(1,:));C(ind)=sign(C(ind)).*((thr/(thr-thrl)*(abs(C(ind))-thrl)));A1=wrcoef2('a',C,S,wname,n);H1=wrcoef2('h',C,S,wname,n);V1=wrcoef2('v',C,S,wname,n);D1=wrcoef2('d',C,S,wname,n);X=A1+H1+V1+D1;