how to apply DWT on a image and to extract energy from all the coeffecients?

how to apply DWT on a image and to extract energy from all the coeffecients?

Answer 1

[Wayne King]

You can obtain a measure of relative contribution (percentage of energy in each of the detail images and the approximation image) with this:

load woman;
dwtmode('per');
[C,S] = wavedec(X,1,'db4');
TE = norm(C,2)^2;
[ca,ch,cv,cd] = dwt2(X,'db4','mode','per');
app_per = 100*(sum(abs(ca(:)).^2))/TE;
horiz_per = 100*(sum(abs(ch(:)).^2))/TE;
vert_per = 100*(sum(abs(cv(:)).^2))/TE;
diag_per = 100*(sum(abs(cd(:)).^2))/TE;