CDF (2,2) Lifting Scheme in Matlab

I made a quick demo of Cohen-Daubechies-Feauveau (2,2) Wavelet Transform using a Lifing Scheme for my class last spring. Here are the predict and update steps:


function s = cdf22_predict(s, level)
step = 2^level;
odds = s(1:step:end-1);
evens = s(2:step:end);
minus1 = [evens(2); evens(1:end-1)];
plus1 = [evens(2:end); evens(end-1)];
s(1:step:end-1) = s(1:step:end-1) - 0.5 * (minus1 + plus1);



function s = cdf22_update(s, level)
step = 2^level;
evens = s(2:step:end);
odds = s(1:step:end-1);
minus1 = [odds(2); odds(1:end-1)];
plus1 = [odds(2:end); odds(end-1)];
s(2:step:end) = s(2:step:end) + 0.25 * (minus1 + plus1);


It was challenging to write these functions without the for loops. You are welcome to download the complete demo here.