[gout]=wav2(gr1,level)

%wav2.m
%constructs the tree structered wavelet transform of 
%the input matrix (down to given level) 
function [gout]=wav2(gr1,level)
[N1 N2]=size(gr1);
if (N1>level),
 gr2=wav1(gr1);
 sb1=gr2(1:N1/2,1:N1/2);
 sb2=gr2(N1/2+1:N1,1:N1/2);
 sb3=gr2(1:N1/2,N1/2+1:N1);
 sb4=gr2(N1/2+1:N1,N1/2+1:N1);
 sub1=wav2(sb1,level);
 sub2=wav2(sb2,level);
 sub3=wav2(sb3,level);
 sub4=wav2(sb4,level); 
 gout(1:N1/2,1:N1/2)=sub1;
 gout(N1/2+1:N1,1:N1/2)=sub2;
 gout(1:N1/2,N1/2+1:N1)=sub3;
 gout(N1/2+1:N1,N1/2+1:N1)=sub4;
else
 gout=gr1;
end;