[SciPy-User] Antwort: Re: scipy.interpolate.interp2d too many data values..

[markus.proeller at ifm.com]

>> I tried to make an interpolation over an 800x600 image with the 
interp2d
>> function from scipy,
>> but I get an error message, that this are "Too many data points to
>> interpolate".
>> It doesn't seem that much data to me. Am I doing anything wrong or how
>> many data does this function support?
>
>Interp2d is mainly meant for interpolation of scattered data, and yes, it 

>has quite low limits on what it handles. It might be possible to bump 
>these upwards, though.
>
>For interpolation of images that are specified on a regular grid, look at 

>scipy.ndimage, especially map_coordinates.

Yes, that's what I was looking for. How do you actaully use it for a RGB 
image?
I used the example from http://www.scipy.org/Cookbook/Interpolation but I 
don't understand how it works for 3-D coordinates.
I want to apply the same remapping stored in y_new, x_new arrays with 2-D 
shape for the 3 channels. Until now I just understand like

>>> coords = array([y_new, x_new])
>>> r = map_coordinates(img_org[:,:,0], coords )
>>> g = map_coordinates(img_org[:,:,1], coords )
>>> b = map_coordinates(img_org[:,:,2], coords )
>>> img = dstack((r,g,b))

But it seems that it can be done shorter...

Thanks,

Markus
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