[vtk-developers] Should ImageViewer2/ImageActor using "Spacing"

[Lisa S. Avila]

Hello Jim,

vtkImageActor does take into account the spacing of the image. How is this 
being lost in the vtkImageView2?

Lisa



At 09:04 AM 10/17/2002, Miller, James V (Research) wrote:
>I spent a few hours last night tracking down a problem with my use of 
>ImageViewer2. Since ImageViewer2 uses the 3D rendering pipeline, I was 
>tricked into thinking it would be trivial to use the ImageViewer2 to show 
>an intensity image and I could simple add another actor to the 
>ImageViewer2's renderer to display a segmentation overlaid on the 
>intensity image.  The segmentation technique uses level sets so I used 
>Marching Squares to extract the zero set as PolyData to overlay on the image.
>
>Now, the output of Marching Squares did not line up properly with the 
>original image.  I believe the issue is that Marching Squares took into 
>account the data spacing while the ImageViewer2/ImageActor combination 
>does not take into account the data spacing.
>
>I know that we have struggled with this in the past, but should the 
>ImageActor use the pixel spacing to determine the "bounds" (and hence the 
>projection) of the image? 'Course sometimes you do want to view an image 
>as if the pixels were isotropic or unit size.  Perhaps it could be a mode 
>to turn on/off pixel spacing.
>
>I has a number of options to get around this issue, scaling my polydata 
>actor, using ImageChangeInformation, etc. so it wasn't too hard to get 
>around.  However, it did take me awhile to determine the use and lack of 
>use of the data spacing was what was causing my grief (I had assumed the 
>problem was with my multi-resolution scale space, not with the rendering...)
>
>  <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />
>
>Jim Miller
>_____________________________________
>Visualization & Computer Vision
>GE Research
>Bldg. KW, Room C218B
>P.O. Box 8, Schenectady NY 12301
>
><mailto:millerjv at research.ge.com>millerjv at research.ge.com
>
>james.miller at research.ge.com
>(518) 387-4005, Dial Comm: 8*833-4005,
>Cell: (518) 505-7065, Fax: (518) 387-6981
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20021017/88eab9c4/attachment.html>