Hello Sam, I looked at the images you provided here:
http://www.cs.utah.edu/~sgerber/tmp/pyramids.zip in Slicer3D. I would agree that test1 from the RecursivePyramid with the shrink filter does not appear to align up correct. So you are likely onto something. What I have found useful for many of these types of geometric filters is to create an image of points of the physical location of center of the pixels, or a set of images if the filter in question doesn't support the multi-component pixels. Then pass this through the filter. Aside from potential boundary conditions the the pixel values of the output should still be the physical location of the pixel in the output. This can create useful and definitive tests. Brad On Jul 17, 2013, at 11:15 AM, sgerber <[email protected]> wrote: > Hi > > RecursiveMultiResolutionPyramidImageFilter behaves significantly different > when using UseShrinkImageFilterOff() vs. UseShrinkImageFilterOn(). The > default, UseShrinkImageFilterOn(), uses for subsampling a single pixel ("top > right" corner) which results, for piecewise constant images, in image > gradients being shifted in physical space. Is this intended? It's not the > behaviour I expected when I used this filter. It is also not documented in > the PyramidFilter documentation or the ShrinkImageFilter that this is the > subsampling method used. > > Thanks > Sam > _______________________________________________ > Powered by www.kitware.com > > Visit other Kitware open-source projects at > http://www.kitware.com/opensource/opensource.html > > Kitware offers ITK Training Courses, for more information visit: > http://kitware.com/products/protraining.php > > Please keep messages on-topic and check the ITK FAQ at: > http://www.itk.org/Wiki/ITK_FAQ > > Follow this link to subscribe/unsubscribe: > http://www.itk.org/mailman/listinfo/insight-developers
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