wavelets on histograms (MPEG-7)

Hello everyone,

I'm actually trying to implement the mpeg-7 scalable color histogram. Well it is simply a 256 bin histogram which they pass through a haar wavelet transformation. I'm not new in matlab, but i am in wavelets. So i'm just checking to see if i got this right. Will the first transform for a histogram H be:

hist=dwt(H,'db1');

the answer is a hist with 128 bins alright, but is it correct????

.