xb2.m

小波二维分解和重构

function ex02()
magic1=imread('disk2.gif');
x=double(magic1);
h=[1 1]/2;
g=[1 -1]/2;
%分解算法
xh=conv2(x,h);%对原矩阵行进行H卷积
xh=dyaddown(xh,0);%下2抽样
%分别进行H，G卷积
     xhh=conv2(xh',h);%对新矩阵列进行H卷积
     xhh=dyaddown(xhh,0);%下2抽样
     xhh=xhh';
     xhg=conv2(xh',g);%对新矩阵列进行G卷积
     xhg=dyaddown(xhg,0);%下2抽样
     xhg=xhg';
     
xg=conv2(x,g);%对原矩阵列进行H卷积
xg=dyaddown(xg,0);%下2抽样
%分别进行H，G卷积
     xgh=conv2(xg',h);%对新矩阵列进行H卷积
     xgh=dyaddown(xgh,0);%下2抽样
     xgh=xgh';
     xgg=conv2(xg',g);%对新矩阵列进行G卷积
     xgg=dyaddown(xgg,0);%下2抽样
     xgg=xgg';
%共生成四个小块xhh,xhg,xgh,xgg

%回复算法
hz=fliplr(h);
gz=fliplr(g);
   %对xhh进行HH卷积
      y2h=dyadup(xhh,0);%上2插值
      y2h=conv2(y2h,hz);%对行H卷积
      y2hh=dyadup(y2h,0);%上2插值
      y2hh=y2hh';
      y2hh=conv2(y2hh,hz);%对列H卷积
      y2hh=y2hh';
   %对xhg进行HG卷积
      y2h=dyadup(xhg,0);%上2插值
      y2h=conv2(y2h,hz);%对行H卷积
      y2hg=dyadup(y2h,0);%上2插值
      y2hg=y2hg';
      y2hg=conv2(y2hg,gz);%对列G卷积
      y2hg=y2hg';
    %对xgh进行GH卷积
      y2g=dyadup(xgh,0);%上2插值
      y2g=conv2(y2g,gz);%对行G卷积
      y2gh=dyadup(y2g,0);%上2插值
      y2gh=y2gh';
      y2gh=conv2(y2gh,hz);%对列H卷积
      y2gh=y2gh'; 
   %对xgg进行GG卷积
      y2g=dyadup(xgh,0);%上2插值
      y2g=conv2(y2g,gz);%对行G卷积
      y2gg=dyadup(y2g,0);%上2插值
      y2gg=y2gg';
      y2gg=conv2(y2gg,gz);%对列H卷积
      y2gg=y2gg';   
   %回复成为四个大块，再将其相加，乘以4，成为原矩阵
     y=y2hh+y2hg+y2gh+y2gg;
     y=y*4;
     y=uint8(y);
     imshow(y);