[AstroPy] got flux-conservative rebinning?

[Sami-Matias Niemi]

Hi Marshall,

The enclosed Python file might contain a function (frebin) that allows you to do what you are looking for (no guarantee that the functionality is correct). It's a very simple dummy solution and you cannot input the zoom factor as percentage or anything fancy like that. Some kind of documentation is here:
http://sammyniemi.com/SamPy/SamPy.image.manipulation.frebin.html


Cheers,
Sami






On 19 Apr 2012, at 18:50, Marshall Perrin wrote:

> 
> 
> While we're fishing for useful algorithms, does anyone have a convenient implementation of flux-conservative rebinning? The image interpolations in  scipy.ndimage are not conservative.  Montage can do this, of course, but that seems like overkill (and adds a lot of interface complexity) if I just want to scale an image by 75% while conserving energy...  Thanks in advance, 
> 
>  - Marshall
> 
> 
> 
> 
> 
> 
> On Apr 13, 2012, at 11:47 AM, Wolfgang Kerzendorf wrote:
> 
>> Hey all,
>> 
>> Thanks for the many suggestions, there seem to be quite a few gems among it. For future reference I have put the suggestions on the astropy wiki (very quick and dirty for now), but hopefully that will help us in the long run when looking for these (only seemingly) simple algorithms to center on an object. Feel free to edit and add to it: https://github.com/astropy/astropy/wiki/2ddata_centroid
>> 
>> I also created a root page for 2ddata utilities at : https://github.com/astropy/astropy/wiki/2ddata_util
>> 
>> Cheers
>>    Wolfgang
>> 
>> On 2012-04-13, at 5:19 PM, Warren J. Hack wrote:
>> 
>>> Wolfgang,
>>> 
>>> There is a star-finding routine in the soon-to-be-officially-released 
>>> drizzlepac package available from STScI.  This routine can be run on its 
>>> own (it is all in Python after all), but a stand-alone interface to run 
>>> just the star finding has not been documented yet.  It is just a single 
>>> function call that requires a numpy array of the image and a few 
>>> numerical parameters and I can point you to examples where it is run 
>>> within a larger task if you contact me directly. Anyone familiar with 
>>> DAOFIND from IRAF will be able to use this code easily.  If you want to 
>>> check it out, you can get this code in pre-release beta form (in binary 
>>> for Mac or source for other platforms) from:
>>> 
>>>     http://stsdas.stsci.edu/irafx
>>> 
>>> We have found that it can provide RMS on point sources of <0.1 pixels 
>>> (and seen 0.03 pix RMS in some cases), but your mileage may vary.
>>> 
>>> Warren Hack
>>> Science Software Branch
>>> STScI
>>> 
>>>> Hey all,
>>>> 
>>>> I just wanted to know if anyone has a quick and smart centroid script in any of the python libraries (easily installable). Even better would be star finding algorithms like sextractor.
>>>> 
>>>> Cheers
>>>>     Wolfgang
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>>> AstroPy at scipy.org
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>> 
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