| Re: scalogram [message #9093] |
Tue, 27 May 1997 00:00 |
Michael Werger
Messages: 34
Registered: May 1997
|
Member |
|
|
Harald Dankworth wrote:
>
> Hi,
>
> I use IDL to compute the wavelet coefficients of a signal and
> present them as a scalogram. The wavelet coefficients are non-uniformly
> distributed over the time-scale plane. My problem is: how do I
> interpolate the intermediate values?
>
> Is anybody familiar with this problem?
>
> Thanks,
>
> Harald Dankworth
--
As long I understand the scalogram representation of
wavelet coefficients, I think you shouldn't interpolate
between intermediate values.
Sloppy spoken:
The scalogram shows the
strength of each wavelet coefficient sorted by the
corresponding resolution scale, i.e. sorted from a coarse
to fine (or vice versa) representation of your data.
So, why do you want to interpolate between some values?
Michael Werger (mwerger@astro.estec.esa.nl)
ESA Astrophysics Division & Praesepe B.V.
ESTEC, Postbus 299, 2200 AG Noordwijk
The Netherlands
|
|
|
|
| Re: scalogram [message #9096 is a reply to message #9093] |
Tue, 27 May 1997 00:00  |
Achim Hein
Messages: 42
Registered: February 1996
|
Member |
|
|
Harald Dankworth wrote:
>
> Hi,
>
> I use IDL to compute the wavelet coefficients of a signal and
> present them as a scalogram. The wavelet coefficients are non-uniformly
> distributed over the time-scale plane. My problem is: how do I
> interpolate the intermediate values?
As I understand you right, you have got the problem that you have
evaluated coefficients and these values do not correspondent to an
equidistant axis - where you came from.
So, you have to do an interpolation to 'fit' the nonequidistant
'distributetd' values in equidistant samples.
If these remarks are correct, there are some methods to 'fit' your
values or let us say there are methods to resample your values.
You can look for any kind of linear or bilinear interpolation.
Furthermore there are the spline interpolations and that's what I
recommend.
Additionally in IDL you have a wonderful simply routine to interpolate
with cubic splines. For some more information look the online help for
SPLINE.
Cheers
Achim
--
_______________________________________________
Dipl.-Ing. A. Hein
PB2 / ZESS - Uni-GH-Siegen
Paul-Bonatz Str. 9-11
57068 Siegen
Phone: 0271/740-3362
Fax: 0271/740-2336
Mail: Hein@nv.et-inf.uni-siegen.de
_______________________________________________
Please have a look at our Web-Sites:
http://www.nv.et-inf.uni-siegen.de/pb2/www_pb2
_______________________________________________
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
