Allow spectral filtering of input data

[JuliaKukulies]

This pull request adds the spectral filtering feature (that has already been added to v2.0-dev though #65) to dev. The main changes I have made to the code are

• to add the function spectral_filtering() in utils.py
• small changes in feature_detection.py to implement the filter step within the feature detection (same as for the optional gaussian filter)
• to add tests for the spectral_filtering() function itself and the filtering option in the feature detection function

For better comprehension what the function does, you can also check out the example notebook

[freemansw1]

Thanks @JuliaKukulies! I wonder if we should target a v1.4 release with these changes (and #138), given that the functionality is already in the v2.x branch and it seems to be well tested and less of a big change than #127 . I'm not sure. Either way, I'll try to get this reviewed next week.

[JuliaKukulies]

@freemansw1 Yes, I totally think we could that and have an intermediate release with this and #138. You are right that the changes are rather small and that it has already been reviewed for v.2 (just note that I have added a unit test that was not there before and that I made small changes in existing functions, so could be good to pay extra attention to that one more time).

What about #136 then? It is quite a lot of new code and a comprehensive new feature, so maybe rather something for 1.5 together with #127, but on the other hand it is also easier to review given that it is just an addition of code rather than changes in existing code. So could also be ready for 1.4 already, if we go for a 1.4 release.

[freemansw1]

@JuliaKukulies Agreed. Let's plan on a 1.4 release with these changes, mergers and splits, and documentation improvements. I've added new 1.3.2 and 1.4 milestones, and have (I hope) moved the appropriate PRs to the appropriate milestones.

[JuliaKukulies]

Perfect, thanks @freemansw1 !

[freemansw1]

I just have a few comments, but I'm happy to approve/merge when we start staging for v1.4.

[codecov]

Codecov Report

Merging #137 (7a27401) into RC_v1.4.0 (6e73fca) will increase coverage by 0.66%.
The diff coverage is 68.42%.

@@              Coverage Diff              @@
##           RC_v1.4.0     #137      +/-   ##
=============================================
+ Coverage      32.09%   32.75%   +0.66%     
=============================================
  Files             11       11              
  Lines           2047     2085      +38     
=============================================
+ Hits             657      683      +26     
- Misses          1390     1402      +12     

Flag	Coverage Δ
unittests	32.75% <68.42%> (+0.66%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
tobac/feature_detection.py	70.16% <26.66%> (-3.94%)	⬇️
tobac/utils.py	46.38% <95.65%> (+5.34%)	⬆️

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[JuliaKukulies]

@freemansw1 I think I have addressed your two remaining points now. Sorry that this resulted in so many commits. I had some issues with the tests, as I had to change the unit at more locations than I thought. But now it should be fine. The main difference to the original PR are

• changed required wavelength units to m instead of km (this included also code changes where dxy was locally changed to get the same unit as the wavelengths, so actually the code should be cleaner now)
• modified test function for spectral_filtering() on data that actually has a wave signal rather than only any random data

[freemansw1]

I'm happy with these changes now! We should wait to merge until we are staging for v1.4.0, but I am happy to merge otherwise.

[JuliaKukulies]

Great, thanks for your review! Yes, we wait for v1.4.0

[freemansw1]

I've moved this to merge into the new RC_v1.4.0 now, so I'm happy for you to merge when ready @JuliaKukulies!

[JuliaKukulies]

All right, thanks @freemansw1! @w-k-jones do you think you wanna have a look as well or should I go ahead and merge?

[freemansw1]

Note with the merge of #138, auto-merging now fails with the documentation being at issue.

[JuliaKukulies]

I went ahead and merged this now after solving the merge conflict with #138, since you approved @freemansw1. I hope that was OK!