Rendering artifact with slab MPR

Support
1

I have a test program to implement slab MPR rendering using vtkImageResliceMapper. I am seeing a strange broken line artifact around the edge of the image after interacting in the viewport.

When the slab MPR image is first displayed it is fine but as soon as I interact with the viewport by clicking on it, the line appears. The vtkInteractorStyleTrackballCamera interactor is enabled and all I need to do is click in the viewport (without moving the mouse) and the line will appear. If I disable the interactor, then the line artifact no longer appears with left click but still appears for the right click used for a popup menu. This artifact appears regardless of slab rendering mode used (mean, max, min) or slice thickness (including setting it to 1)

This is a java application that uses the java wrappers and a vtkRenderWindowPanel is being used for display. Here are some sample images, the first is the initial slab image that gets display with no line artifact:

slab-no-line
slab-no-line571×445 34.2 KB

Here is the slab image after simply clicking in the viewport … in this case the line is solid but only appears on two of the edges:

slab-line
slab-line519×438 34.2 KB

Lastly here is the slab image after rotating the image plane and camera … in this case the line is dashed and appears on all edges:

slab-line2
slab-line2529×449 36.7 KB

I have tried numerous different things but the result is always the same, as soon as I click in the viewport, the slab image will always display some sort of a line artifact around the edges. Lastly I will mention that regular MPR (slab not enabled) works fine as does volume rendering, no line artifacts. Any suggestions would be greatly appreciated.

2

Try calling AutoAdjustImageQualityOff() on the vtkImageResliceMapper.

When a mouse button is pressed, the interactor reduces VTK’s “AllocatedRenderTime” and this causes the mapper to automatically switch to a faster rendering method that has slightly lower quality for oblique views. The AutoAjustImageQuality setting controls whether this switching occurs.

I’ve been trying to replicate your artifact on my own system, and so far I haven’t been able to. Can you provide details about your program and your system? Such as:

a) operating system and GPU
b) any settings that you have applied to the vtkImageResliceMapper
c) any settings that you have applied to the vtkImageProperty

And about the image itself:

d) the data range, is the lowest value 0 or is it -1000?
e) what are the dimensions and pixel spacings?