[Scipy-tickets] [SciPy] #213: ndimage.rotate creates artifacts (general problem in ndimage.spline_filter)

SciPy scipy-tickets@scipy....
Wed Mar 14 14:22:29 CDT 2007


#213: ndimage.rotate creates artifacts (general problem in ndimage.spline_filter)
---------------------------+------------------------------------------------
 Reporter:  stefan         |        Owner:  somebody
     Type:  defect         |       Status:  new     
 Priority:  normal         |    Milestone:          
Component:  scipy.ndimage  |      Version:  devel   
 Severity:  normal         |   Resolution:          
 Keywords:                 |  
---------------------------+------------------------------------------------
Changes (by zachrahan):

  * summary:  ndimage.rotate creates artifacts => ndimage.rotate creates
              artifacts (general problem in
              ndimage.spline_filter)

Comment:

 This is a general problem in ndimage.spline_filter, which causes artifacts
 in all of the image resampling functions in ndimage.interpolate:

 nd.interpolation.affine_transform
 nd.interpolation.geometric_transform
 nd.interpolation.map_coordinates
 nd.interpolation.rotate
 nd.interpolation.shift
 nd.interpolation.zoom

 The problem seems to be ringing in the spline around sharp intensity
 changes, but it appears even in continuous-tone images. It's not related
 to the numeric precision of the input array type, either. The ringing gets
 worse the higher-order the spline is.

-- 
Ticket URL: <http://projects.scipy.org/scipy/scipy/ticket/213#comment:1>
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