Re: [Bug-gsl] GSL Wavelet Transform

[JIA Pei]

Yes, that is my point. I really would like the dwt step in dwt.c to be
exported for public use.
The applications could be found in image processing.

You may find a typical image at the right hand side  from
http://en.wikipedia.org/wiki/Discrete_wavelet_transform


I believe this image has not been transformed till level log2(N)


Probably, if you transformed more levels, you lost more data. Because
wavelet can be looked on as a lossy compression, some times, if the users
would like to analyze the compression ratio and the quality of the
reconstructed images--- it's not that useful, but there might be such kind
of requirements.


So, is it possible that GSL affords the the "levels" as a public parameter?


Best Regards
JIA Pei





On Fri, Jul 24, 2009 at 12:25 PM, Brian Gough <address@hidden> wrote:

> At Tue, 21 Jul 2009 01:12:10 +0100,
> JIA Pei wrote:
> >
> > GSL is always trying to do the wavelet transform till level log2(N),
> which
> > can't satisfy the users' requirement, because it is true that some times,
> > the users  would like to carry out wavelet transform just until level 2.
> >
> > So, any possibility to improve this issue?
>
> Would you like the internal function dwt_step in dwt.c to be exported
> for public use, or some other way?  What's the application of not
> doing a full transform?
>
> --
> Brian Gough
> (GSL Maintainer)
>
> Support freedom by joining the FSF
> http://www.fsf.org/associate/support_freedom/join_fsf?referrer=37
>



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