xiaobobao

代码说明：

   ch3=softt(h3,thr1 clear clc I=imread( lena512.bmp ) imshow(I) I=double(I) II=I+30*randn(size(I)) figure imshow(II,[]) [a1,h1,v1,d1]=dwt2(II, sym8 ) [a2,h2,v2,d2]=dwt2(a1, sym8 ) [a3,h3,v3,d3]=dwt2(a2, sym8 ) sigma=median(abs(d1(:)))/0.6745 x=3*sigma thr1=x*2^(-1) thr2=x*2^(-0.5) thr3=x 小波图像去噪( ch3=softt(h3,thr1 clear clc I=imread( lena512.bmp ) imshow(I) I=double(I) II=I+30*randn(size(I)) figure imshow(II,[]) [a1,h1,v1,d1]=dwt2(II, sym8 ) [a2,h2,v2,d2]=dwt2(a1, sym8 ) [a3,h3,v3,d3]=dwt2(a2, sym8 ) sigma=median(abs(d1(:)))/0.6745 x=3*sigma thr1=x*2^(-1) thr2=x*2^(-0.5) thr3=x )