% [LEV,IND] = wpyrLev(PYR,INDICES,LEVEL)
%
% Access a level from a separable QMF/wavelet pyramid.
% Return as an SxB matrix, B = number of bands, S = total size of a band.
% Also returns an Bx2 matrix containing dimensions of the subbands.

% Eero Simoncelli, 6/96.

function [lev,ind] = wpyrLev(pyr,pind,level)

if ((pind(1,1) == 1) | (pind(1,2) ==1))
nbands = 1;
else
nbands = 3;
end

if ((level > wpyrHt(pind)) | (level < 1))
error(sprintf('Level number must be in the range [1, %d].', wpyrHt(pind)));
end

firstband = 1 + nbands*(level-1)
firstind = 1;
for l=1:firstband-1
firstind = firstind + prod(pind(l,:));
end

ind = pind(firstband:firstband+nbands-1,:);
lev = pyr(firstind:firstind+sum(prod(ind'))-1);