function waveshow(w)

[m,n]=size(w);
subplot(2,2,1,'align'); imshow(w(1:m/2,1:m/2),[]);
subplot(2,2,2,'align'); imshow(w(1:m/2, m/2+1:end),[]);
subplot(2,2,3,'align'); imshow(w(m/2+1:end,1:m/2),[]);
subplot(2,2,4,'align'); imshow(w(m/2+1:end,m/2+1:end),[]);
[norm(w(1:m/2,1:m/2),'fro') norm(w(1:m/2, m/2+1:end), 'fro')  norm(w(m/2+1:end,1:m/2),'fro') norm(w(m/2+1:end,m/2+1:end),'fro')]