維小波變換MATLAB實(shí)現(xiàn)ppt課件

1、二維小波變換MATLAB實(shí)現(xiàn) dwt2函數(shù) 功能：二維離散小波變換 格式：cA,cH,cV,cD=dwt2(X,wname) cA,cH,cV,cD=dwt2(X,Lo_D,Hi_D) 闡明：cA,cH,cV,cD=dwt2(X,wname)運(yùn)用指定的小波基函數(shù)wname對(duì)二維信號(hào)X進(jìn)展二維離散小波變幻；cA，cH,cV,cD分別為近似分量、程度細(xì)節(jié)分量、垂直細(xì)節(jié)分量和對(duì)角細(xì)節(jié)分量；cA,cH,cV,cD=dwt2(X,Lo_D,Hi_D)運(yùn)用指定的分解低通和高通濾波器Lo_D和Hi_D分解信號(hào)X。 load woman; nbcol = size(map,1);%前往矩陣的行數(shù)和列數(shù) cA1

2、,cH1,cV1,cD1 = dwt2(X,db1); cod_x=wcodemat(X,nbcol);%前往矩陣X的編碼矩陣，nbcol為編碼的最大值 cod_cA1=wcodemat(cA1,nbcol); cod_cH1=wcodemat(cH1,nbcol); cod_cV1=wcodemat(cV1,nbcol); cod_cD1=wcodemat(cD1,nbcol); dec2d=cod_cA1,cod_cH1;cod_cV1,cod_cD1; subplot(1,2,1),imshow(cod_x,); title(量化后的圖像); subplot(1,2,2),imshow(

3、dec2d,); title(二維離散小波分解后的圖像); idwt2函數(shù) 功能：二維離散小波反變換 格式：X=idwt2(cA,cH,cV,cD,wname) X=idwt2(cA,cH,cV,cD,Lo_R,Hi_R) X=idwt2(cA,cH,cV,cD,wname,S) X=idwt2(cA,cH,cV,cD,Lo_R,Hi_R,S) 闡明：X=idwt2(cA,cH,cV,cD,wname)由信號(hào)小波分解的近似信號(hào)cA和細(xì)節(jié)信號(hào)cH、cH、cV、cD經(jīng)小波反變換重構(gòu)原信號(hào)X；X=idwt2(cA,cH,cV,cD,Lo_R,Hi_R)運(yùn)用指定的重構(gòu)低通和高通濾波器Lo_R和Hi_R

4、重構(gòu)原信號(hào)X；X=idwt2(cA,cH,cV,cD,wname,S)和X=idwt2(cA,cH,cV,cD,Lo_R,Hi_R,S)前往中心附近的S個(gè)數(shù)據(jù)點(diǎn)。 load woman; sX=size(X); cA1,cH1,cV1,cD1=dwt2(X,db4); A0=idwt2(cA1,cH1,cV1,cD1,db4,sX); subplot(1,2,1),imshow(X,) title(原始圖像); subplot(1,2,2),imshow(A0,) title(由二維小波分解重構(gòu)后的圖像); wavedec2函數(shù) 功能：二維信號(hào)的多層小波分解 格式：C,S=wavedec2(X

5、,N,wname) C,S=wavedec2(X,N,Lo_D,Hi_D) 闡明：C,S=wavedec2(X,N,wname)用小波基函數(shù)wname對(duì)二維信號(hào)X進(jìn)展N層分解；C,S=wavedec2(X,N,Lo_D,Hi_D)用指定的分解低通和高通濾波器Lo_D和Hi_D分解信號(hào)X。 waverec2函數(shù) 闡明：二維信號(hào)的多層小波重構(gòu) 格式：X=waverec2(C,S,wname) X=waverec2(C,S,Lo_R,Hi_R) 闡明：X=waverec2(C,S,wname)由多層二維小波分解的結(jié)果C、S重構(gòu)原始信號(hào)X，wname為運(yùn)用的小波基函數(shù)；X=waverec2(C,S,L

6、o_R,Hi_R)運(yùn)用重構(gòu)低通和高通濾波器Lo_R和Hi_R重構(gòu)原信號(hào)。 load woman; c,s=wavedec2(X,2,sym4); a0=waverec2(c,s,sym4); subplot(1,2,1),imshow(X,) title(原始圖像); subplot(1,2,2),imshow(a0,) title(重構(gòu)后的圖像);appcoef2提取二維信號(hào)小波分解的近似分量 load woman;c,s=wavedec2(X,3,db1);%用db1小波進(jìn)展三層分解ca1=appcoef2(c,s,db1,1);%提取一層近似分量ca2=appcoef2(c,s,db2,

7、2);%提取二層近似分量imshow(X,);title(原始圖像);figure,imshow(ca1,)title (第一層近似分量);figure,imshow(ca2,)title(第二層近似分量);detcoef2提取二維信號(hào)小波分解的細(xì)節(jié)分量load woman;c,s=wavedec2(X,3,db1);chd2=detcoef2(h,c,s,1);cvd2=detcoef2(v,c,s,1);cdd2=detcoef2(d,c,s,1);imshow(X,)title(原始圖像);figuresubplot(1,3,1),imshow(chd2,)title(第一層分解的程度細(xì)

8、節(jié));subplot(1,3,2),imshow(cvd2,)title(第一層分解的垂直細(xì)節(jié));subplot(1,3,3),imshow(cdd2,)title(第一層分解的對(duì)角細(xì)節(jié));wrcoef2由多層小波分解重構(gòu)某一層的分解信號(hào) clear allload wbarb;image(X);colormap(map);colorbar;I=ind2gray(X,map);figure;I=imadjust(I,stretchlim(I),0,1);imshow(I);%j=imadjust(i,low_in;high_in,low_out,high_out) 將 i 中的亮度值映射到 j

9、 中的新值wname=sym2;c,s=wavedec2(I,2,wname);cA1=appcoef2(c,s,wname,1);ch1,cv1,cd1=detcoef2(all,c,s,1);cA2=appcoef2(c,s,wname,2);ch2,cv2,cd2=detcoef2(all,c,s,2);a1=wrcoef2(a,c,s,wname,1);h1=wrcoef2(h,c,s,wname,1);v1=wrcoef2(v,c,s,wname,1);d1=wrcoef2(d,c,s,wname,1);a2=wrcoef2(a,c,s,wname,2);h2=wrcoef2(h,c

10、,s,wname,2);v2=wrcoef2(v,c,s,wname,2);d2=wrcoef2(d,c,s,wname,2);figure;subplot(2,2,1);a1=abs(a1);a1=imadjust(a1,stretchlim(a1),0,1);imshow(a1);title(approximation a1)subplot(2,2,2);h1=abs(h1);h1=imadjust(h1,stretchlim(h1),0,1);imshow(h1);title(horizontal detail h1)subplot(2,2,3);v1=abs(v1);v1=imadju

11、st(v1,stretchlim(v1),0,1);imshow(v1);title(vertical detail v1)subplot(2,2,4);d1=abs(d1);d1=imadjust(d1,stretchlim(d1),0,1);imshow(d1);title(diagonal detail d1)figure;subplot(2,2,1);a2=abs(a2);a2=imadjust(a2,stretchlim(a2),0,1);imshow(a2);title(approximation a2)subplot(2,2,2);h2=abs(h2);h2=imadjust(h

12、2,stretchlim(h2),0,1);imshow(h2);title(horizontal detail h2)subplot(2,2,3);v2=abs(v2);v2=imadjust(v2,stretchlim(v2),0,1);imshow(v2);title(vertical detail v2)subplot(2,2,4);d2=abs(d2);d2=imadjust(d2,stretchlim(d2),0,1);imshow(d2);title(diagonal detail d2)upcoef2由多層小波分解重構(gòu)近似分量或細(xì)節(jié)分量 load woman;c,s=wavedec2(X,2,db4);siz=s(size(s,1),:);cal=appcoef2(c,s,db4,1);a1=upcoef2(a,cal,db4,1,siz);chd1=detcoef2(h,c,s,1);hd1=upcoef2(h,chd1,db4,1,siz);cvd1=detcoef2(v,c,s,1);vd1=upcoef2(h,cvd1,db4,1,siz);cdd1=detcoef2(d,c,s,1)