[Scipy-tickets] [SciPy] #1641: Unexpected behavior in ni_filters.c/NI_Correlate

SciPy Trac scipy-tickets@scipy....
Fri Apr 13 17:44:18 CDT 2012

#1641: Unexpected behavior in ni_filters.c/NI_Correlate
 Reporter:  eschlafly  |       Owner:  somebody   
     Type:  defect     |      Status:  new        
 Priority:  normal     |   Milestone:  Unscheduled
Component:  Other      |     Version:  0.9.0      
 Keywords:             |  
 scipy.ndimage.correlate surprised me today by using a smaller convolution
 kernel than I had given it.  The problem is that NI_Correlate in
 ni_filters.c only uses bits of the kernel larger than DBL_EPSILON.  If the
 whole kernel is smaller than that, the convolution becomes a noop.

 At the least the documentation should reflect this behavior.  Ideally, I
 would like the option to turn this feature off.  In my own case, I was
 smoothing a single bright pixel with a large Gaussian kernel, and couldn't
 figure out why nonzero part of the resulting image was much smaller than
 the kernel.

 I'm using 0.9 but it looks like it is still in 0.10.

Ticket URL: <http://projects.scipy.org/scipy/ticket/1641>
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