[Scipy-tickets] [SciPy] #1570: Some scipy.ndimage functions fails for Yx1024x1024 images
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Sun Dec 11 09:40:16 CST 2011
#1570: Some scipy.ndimage functions fails for Yx1024x1024 images
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Reporter: chcomin | Owner: somebody
Type: defect | Status: new
Priority: high | Milestone: Unscheduled
Component: scipy.ndimage | Version: 0.9.0
Keywords: image dimension correlate |
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Old description:
> When you use some functions in scipy.ndimage you get unexpected results
> for three dimensional images where two dimensions have size 1024, for
> example:
>
> img = numpy.ones([1,1023,1023])
> s = numpy.ones([3,3,3])
> res = scipy.ndimage.filters.correlate(img,s)
>
> the output, as expected, is the number 27 for every element of res (the
> sum of s).
>
> Now, if you change img dimension to 1024:
>
> img = numpy.ones([1,1024,1024])
> s = numpy.ones([3,3,3])
> res = scipy.ndimage.filters.correlate(img,s)
>
> you get strange values that are wrong.
>
> With a two dimensional matrix everything is fine:
>
> img = numpy.ones([1024,1024])
> s = numpy.ones([3,3])
> res = scipy.ndimage.filters.correlate(img,s)
>
> every element of res is 9.
>
> This error also happens with scipy.ndimage.measurements.label and
> probably with other functions (maybe they all use correlate?)
>
> So far I verified that the error occurs in scipy 0.9 and 0.10.
New description:
When you use some functions in scipy.ndimage you get unexpected results
for three dimensional images where two dimensions have size 1024, for
example:
{{{
img = numpy.ones([1,1023,1023])
s = numpy.ones([3,3,3])
res = scipy.ndimage.filters.correlate(img,s)
}}}
the output, as expected, is the number 27 for every element of res (the
sum of s).
Now, if you change img dimension to 1024:
{{{
img = numpy.ones([1,1024,1024])
s = numpy.ones([3,3,3])
res = scipy.ndimage.filters.correlate(img,s)
}}}
you get strange values that are wrong.
With a two dimensional matrix everything is fine:
{{{
img = numpy.ones([1024,1024])
s = numpy.ones([3,3])
res = scipy.ndimage.filters.correlate(img,s)
}}}
every element of res is 9.
This error also happens with scipy.ndimage.measurements.label and probably
with other functions (maybe they all use correlate?)
So far I verified that the error occurs in scipy 0.9 and 0.10.
--
Comment(by warren.weckesser):
Add markup to description.
--
Ticket URL: <http://projects.scipy.org/scipy/ticket/1570#comment:2>
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