[vtkusers] Large Volume Data

[David Netherway]

Large Volume DataTry using  vtkImageClip instead of vtkExtractVOI. There was an earlier message that suggested that the latter still requires the whole dataset to be loaded wheras the former does not.

  ----- Original Message ----- 
  From: FICKER, MICHAEL 
  To: 'vtkusers at public.kitware.com' 
  Sent: Tuesday, 06 August, 2002 10:48 AM
  Subject: [vtkusers] Large Volume Data


  My data set consists of 1500 jpeg images of 2000x2000 pixels each.  I do not intend to visualize such a large volume but I was trying to make VTK extract and resample my Volume of Interest (VOI) and then dump this smaller volume (aprox 150x150x150) out into a new set of jpegs.

  I have had luck manipulating and visualizing smaller volumes but have been unable to use such a large data set.  I have tried various forms of vtkImageDataStreamer and vtkMemoryLimitImageDataStreamer.

  I have been trying varios forms of the following script.  If I only procecss ~350 images it runs fine, but if I try the entire stack VTK crashes.

  Time is not a concern, the script can run as long as it takes. 
  Any ideas on how to work with datasets this large? 



  # read a stack of images starting at GR0000.JPG 
  vtkJPEGReader reader 
          reader SetFilePrefix "GR" 
          reader SetDataExtent 0 2000 0 2000 0 1500 
          reader SetFilePattern "%s%04d.JPG" 
          reader SetDataSpacing 2 2 3 
          reader SetDataScalarTypeToUnsignedShort 
          reader GlobalReleaseDataFlagOn 

  #Stream the data to comsume less memory 
  vtkImageDataStreamer streamer 
          streamer SetInput [reader GetOutput] 
          streamer SetNumberOfStreamDivisions 32 
          [streamer GetExtentTranslator] SetSplitModeToBlock 
          streamer UpdateWholeExtent 

  # Extract and resample a sub volume from the source 
  vtkExtractVOI voi 
          voi SetInput [streamer GetOutput] 
          voi SetVOI 500 1500 400 1600 100 1400 
          voi SetSampleRate 10 10 10 
          [voi GetOutput] SetScalarTypeToUnsignedChar 

  # write out the new smaller volume 
  vtkJPEGWriter writer 
          writer SetInput [voi GetOutput] 
          writer SetFilePrefix "vol" 
          writer SetFilePattern "%s%04d.jpg" 
          writer SetFileDimensionality 3 
          writer Write 

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