function y=IWT(level, wfil, w)
% IWT(l,wfil,w)  perform l level inverse wavelet transform using wavelet
% filter wfil.  Acts columnwise. 

[datalength,numsamples]=size(w);
y=w;
for j=level:-1:1
    m=datalength/2^(j-1);
    y(1:m,:)=waverec(wfil,y(1:m,:));
end