[Insight-users] Re: 3D Image to voxel conversion

[Luis Ibanez]

Hi Subbu,


1) You can read a collection of 2D images from files
    and create a 3D volume by using the ImageSeriesReader.

    Please read the "Reading and Writing Images" chapter of
    the ITK Software Guide

       http://www.itk.org/ItkSoftwareGuide.pdf


1.5) You must not believe everything that you read in
      articles, especially if they are not accompanied
      by source code and images that allow to reproduce
      an experiment. Papers that only contain text and
      pictures are to be read as nice stories of legendary
      adventures.

      The claim that it is possible to segment a CT slice by
      using thresholding, is sometimes true and sometimes false.

      It all depends of what you are trying to segment and
      what CT protocol was used for the acquisition. The
      fact that somebody may have succeeded to perform a
      segmentation from a CT slice using just thresholding
      is an *interesting anecdotic information*, but apart
      from that is *technically useless* information.


2)  If your initial images have anisotropic pixels, that
     information is propagated by ITK filters upto the
     final segmentations.  If you obtained your segmentation
     by using a different tool, then you have to go back
     to the original images and recover the Origin and Spacing
     information.



   Regards,


      Luis



===================
K. Subburaj wrote:
> Hi Luis,
> 
> Thanks for giving good suggestion for my previous queries. I hav some
> basic things which may be out of itk scope, can u help me to get answer?
> 
> 1. I want to know that is there any way to convert segmented 3D image
> (series of stacked 2D slices) into direct voxel (3d) structure (N*N*M)
> like one slice into one layer of structure, using itk, other than going
> for vtk mesh.
> 
>  (also i read an article that for CT slice data only thresholding is
> sufficient  for segmenting data bcaz of boundary (edge) pixels clear
> distinction than other pixels, is it so?, if yes, then why these many
> segmentation algo? )
> 
> 2. How can i get anisotrophic inter pixel distance and inter slice
> distance for volume conversion from segmented image?. or do i need to get
> these values from initial images reading and keep it for conversion?
> 
> I am using input files in DICOM format and ITK 3.0.
> 
> Thanks / Subbu
> 
> 
> 
>