someshsandbox/vtkimagesmoothingbug

vtkImageSmoothingBug

vtkImageSmoothingBug

vtkImageSmoothingBug

When displaying images with sharp edges, a smoothing / anti-aliasing effect is seen. The same image, when viewed in ITK-SNAP, shows sharp edges.

See screenshots folder for screenshots for VTK and ITK-SNAP rendering.

This test program displays the DICOM image in "data" folder.

Toggle variable USE_VTKIMAGE_VIEWER to display data using either vtkImageViewer2 or vtkImageActor. The smoothing/anti-aliasing effect is visible in both cases.

Update : Based on discussion on vtk users list, I found that this is not a bug. However, if you want the data not to be interpolated, see below :

Reply From David Gobbi on [email protected]

It's definitely not a bug. Interpolation is turned on by default, in order to reduce a certain artifact known as "pixels" that can occur when displaying a uniformly sampled data set ;)

In VTK 5, use this method:

actor->InterpolateOff();

In VTK 6, you can have even more control via the Property and the Mapper for the image:

actor->GetProperty()->SetInterpolationTypeToNearest(); actor->GetMapper()->BorderOn();