[SciPy-user] Explanation of different edge modes in scipy.ndimage

Kurt Smith kwmsmith@gmail....
Tue Nov 4 09:26:25 CST 2008


On Tue, Nov 4, 2008 at 3:30 AM, Stéfan van der Walt <stefan@sun.ac.za>wrote:

> Hi Kurt
>
> 2008/10/31 Kurt Smith <kwmsmith@gmail.com>:
> > I'm doing some gaussian filtering of periodic 2D arrays using
> > scipy.ndimage.gaussian_filter.  There is a 'mode' argument that is set to
> > 'reflect' by default.  In _ni_support.py:34 there is a conversion
> function,
> > '_extend_mode_to_code' that gives the different modes available.  For
> > periodic data I believe I should use 'wrap', but I'm interested to know
> what
> > the other modes mean, esp the difference between 'reflect' and 'mirror'.
> > For the record, the modes defined are 'nearest', 'wrap', 'reflect',
> > 'mirror', and 'constant'.  For future reference, is there a place where
> > these arguments are documented?
>
> Sorry for the long overdue reply.
>
> Reflect means:
>
> 1 | 2 | 3 | 2 | 1
>
> While mirror means:
>
> 1 | 2 | 3 | 3| 2 | 1
>
> (or the other way around, can't remember).
>
> The problem with the last approach is the interpolation between 3 and
> 3, which is currently broken, so I'd advise against using it.



Thanks Stefan.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://projects.scipy.org/pipermail/scipy-user/attachments/20081104/2321f4ef/attachment.html 


More information about the SciPy-user mailing list