X=imread('E:\matlab1\LENAcaise64.bmp','bmp');
 [Y,map]=rgb2ind(X,128);
Wavelet_Name='db1';
Wavelet_Scale=1;
 [C,S]=wavedec2(double(Y),Wavelet_Scale,Wavelet_Name);
LL1=appcoef2(C,S,Wavelet_Name,Wavelet_Scale);
LH1=detcoef2('v',C,S,1);
HL1=detcoef2('h',C,S,1);
HH1=detcoef2('d',C,S,1);
a=round(0.5*size(LL1,1));
b=round(0.5*size(LL1,2));
ca=LL1(1:a,1:b);
figure(1);imshow(ca,map);
[nca,nmap]=imapprox(round(double(ca)),map,256);
figure(2);
subimage(nca,nmap);
whos;