Thread Subject: Wavelet Reconstruct

Hi friends
I decompose a signal in wavelet using 'db4' in 8 level
and I want to reconstruct a signal with only details
between detail(3) to detail(5)
how can i do it?
thanks

"ehsan mirrahimi" <ehsan.mirrahimi@mathworks.com> wrote in
message <fd0h2s$ii2$1@fred.mathworks.com>...
> Hi friends
> I decompose a signal in wavelet using 'db4' in 8 level
> and I want to reconstruct a signal with only details
> between detail(3) to detail(5)
> how can i do it?
> thanks

I think all you have to do is multiply all of the detail
you don't want to include by 0, then do the inverse wavelet
transform on the lot.

Hope that helps

Regards

Dave Robinson

"Dave Robinson" <dave.robinson@somewhere.biz> wrote in
message <fd0jlr$dsa$1@fred.mathworks.com>...
> "ehsan mirrahimi" <ehsan.mirrahimi@mathworks.com> wrote in
> message <fd0h2s$ii2$1@fred.mathworks.com>...
> > Hi friends
> > I decompose a signal in wavelet using 'db4' in 8 level
> > and I want to reconstruct a signal with only details
> > between detail(3) to detail(5)
> > how can i do it?
> > thanks
>
> I think all you have to do is multiply all of the detail
> you don't want to include by 0, then do the inverse wavelet
> transform on the lot.
>
> Hope that helps
>
> Regards
>
> Dave Robinson
>

If you use the discrete transform ([c,l] = wavedec(...)) to
decompose your original signal, then all you have to do is
use waverec to reconstruct. but before doing so, as dave
suggested, just set the detail coefficients to zero from the
other levels you don't want to include. you can figure out
which elements of the transform coefficients vector
correspond to which level according to the bookkeeping
vector 'l'. (help waverec).

if you originally decomposed using continuous transform
(cwt), then the approach is still the same, but you'll first
need the function for the inverse cwt, which is how i got to
your question in the first place!

maybe i'll get unlazy and just write it.

in the meanwhile, if anyone has it already written, I would
be most appreciative if you'd post it. probably a lot of
other people would love you for it too.