[AstroPy] Interested in a wavelet toolbox?

Christoph Deil deil.christoph at googlemail.com
Thu Apr 2 18:33:38 EDT 2015

> On 02 Apr 2015, at 23:40, Ricky Egeland <ricky.egeland at gmail.com> wrote:
> I was searching for a well-tested wavelet library in Python a few months ago, and did not find anything fully satisfactory.  I wanted a continuous wavelet transform using the Morlet mother wavelet, with significance contours.  I feel like such a package belongs in scipy more than it does astropy, as wavelets are a general signal processing technique not restricted to astronomy.

Hi Amara,

I agree with Ricky here … a good wavelets toolbox belongs in Scipy because it’s useful to many scientist and engineers.
If you can contribute there, here’s a starting point: https://github.com/scipy/scipy/issues/3931 <https://github.com/scipy/scipy/issues/3931> (and I’ve put Ralf Gommers as lead on this effort in CC).

Then there’s probably going to be astronomy-specific wavelets and wavelet methods and these could go in Astropy or an Astropy-affiliated package.
But I don’t think we should duplicate the functionality that’s already implemented in the packages listed below and that will hopefully soon become available in Scipy.


>  There are a few wavelet-related functions in scipy.signal already, but they do not work together (e.g. scipy.signal.cwt is unrelated to scipy.signal.morlet) and it is not clear how they are intended to be used.  I have seen scipy discussions that propose throwing all that away and starting over.
> In case they are useful, here are my notes from the search:
> ===
> - scipy.signal.wavelet : cwt(), only Mexican hat wavelet?  Poor documentation
> - kPyWavelet : https://github.com/Cadair/kPyWavelet/
>   Linked from http://ocgweb.marine.usf.edu/~liu/wavelet.html
>   Few users... real interest?
> - A Practical Guide to Wavelet Analysis
>   http://paos.colorado.edu/research/wavelets/
>   Highly cited ... no python
> - pycwt
>   https://github.com/regeirk/pycwt
>   Explicitly based on T&C code above
>   # Tested.  Example code has a few minor bugs, but appears to be doing the right thing
> - PyCWT
>   https://github.com/Unidata/pyCWT
>   Simple, 1 file
>   Based on T&C
>   # Tested. No example code, but docstrings have examples (that don't work as-is)  Source code is cleaner than pycwt.  scaleogram() has some issues.  Need to input scales, not frequencies...
> - ObsPy
>   http://docs.obspy.org/master/tutorial/code_snippets/continuous_wavelet_transform.html
> - PyWavelets
>   http://www.pybytes.com/pywavelets/
>   Part of MacPorts
>   Good documentation effort
>   Only one developer, but 5+ years effort
> - https://github.com/aaren/wavelets
> - https://pypi.python.org/pypi/waipy
>   Based on T&C code
> - scipy wavelet discussions: https://github.com/scipy/scipy/issues?utf8=✓&q=is%3Aissue+is%3Aopen+wavelet
> ===
> In the end I forked Unidata/pyCWT, fixed a few things and used that (https://github.com/rickyegeland/pyCWT).  On a second look I decided regeirk/pycwt might have been the better implementation, but the interface and documentation were not the best for getting started.
> Hope this helps.
> Regards,
> Ricky Egeland
> On Apr 2, 2015, at 12:47 PM, Amara Graps <amara at konteur.com> wrote:
>> Greetings astropy-ers,
>> I'm proposing the development of a wavelet library in Python to a
>> (European Commission) funding agency and I'll need beta testing
>> of some parts. I think it would be especially great to have the
>> library be incorporated into AstroPy after it's written and tested
>> because the funds for maintenance would end when the project ends..
>> yet astronomers continue to love wavelets.
>> Some large part of my Python wavelet library would be built upon this
>> well-established (general purpose) Matlab toolbox:
>> http://statweb.stanford.edu/~wavelab/Wavelab_850/index_wavelab850.html
>> Does this sound useful and interesting to this group? If it does, please
>> reply to graps at psi.edu. I'm gathering documentation of the AstroPy user
>> community's interest and my testing and maintenance methodology in order
>> to help the project get funded.
>> Thanks very much in advance!
>> Sincerely,
>> Amara
>> Amara Graps, PhD
>> Lead Researcher,  University of Latvia
>> Astronomijas institūts, Raiņa bulvāris 19, Rīga, LV-1050, Latvia
>> amara at lu.lv  +371 / 28853907
>> and
>> Senior Scientist, Planetary Science Institute (PSI, USA),
>> Aleksandra Caka iela, 96-31,
>> Riga, Latvia LV-1011
>> http://www.psi.edu/about/staff/graps/graps.html
>> graps at psi.edu  +1 / 644-6250
>> _______________________________________________
>> AstroPy mailing list
>> AstroPy at scipy.org
>> http://mail.scipy.org/mailman/listinfo/astropy
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