[Insight-users] setSpacing() Ignored writing to files

[Bill Lorensen]

Felix,

I just looked at the code in itkTIFFImageIO.cxx. We do in fact compute a
spacing on read if it exists. We don't write the spacing however.

Here is the dilemma. TIFF supports units of measurement. Either inches,
centimeters or none. In itk, we don't specify units although for medical
imaging they are usually mm's. At write time, we don't know what units to
specify. We could assume mm's and convert that to cm's I guess.

Bill
On Jan 24, 2008 11:08 AM, Bill Lorensen <bill.lorensen at gmail.com> wrote:

> Felix,
>
> I don't believe that png supports spacing in the header. tiff might, but
> maybe we aren't writing the spacing. Can you file a bug following the
> procedure in:
>
> http://www.itk.org/Wiki/ITK_Procedure_for_Contributing_Bug_Fixes
>
> Thanks,
>
> Bill
>   On Jan 24, 2008 10:49 AM, Felix Bollenbeck <bollen at ipk-gatersleben.de>
> wrote:
>
> > Hi ITK Users!
> >
> > I'm having troubles writing the spacing to a transformed image.
> > Although the resampler gets the input-image spacing, the written image
> > which is read in the next iteration has the default [1 1] spacing
> > causing troubles.
> >
> > The images are written to tiff files and haven an initial spacing of
> > .37... after transformation and writing, i read files with [1 1]
> > spacing, although
> >
> >  resample->SetOutputSpacing(fixedImage->GetSpacing());
> >
> > and fixed image has [.37 .37]!
> >
> > I have tried png files too, in case this is a TIF specific issue same-so
> > I conclude it is my mistake here, but where?
> >
> > Thanks for your help,
> >
> > Felix.
> >
> >
> >
> >
> >
> >
> >  resample->SetSize(    fixedImage->GetLargestPossibleRegion().GetSize()
> > );
> >  resample->SetOutputOrigin(fixedImage->GetOrigin());
> >  resample->SetOutputSpacing(fixedImage->GetSpacing());
> >  resample->SetDefaultPixelValue(0);
> >  resample->Update();
> >
> > //#############
> >  const SpacingType outSpacing = resample->GetOutputSpacing();
> >  std::cout <<"SIZE spacing-out  " << outSpacing[0]<< "    " <<
> > outSpacing[1] << std::endl;
> > //#############
> >
> >
> >  typedef  unsigned char  OutputPixelType;
> >  typedef itk::Image< OutputPixelType, Dimension > OutputImageType;
> >  typedef itk::CastImageFilter< FixedImageType,OutputImageType >
> > CastFilterType;
> >  typedef itk::ImageFileWriter< OutputImageType >  WriterType;
> >
> >
> >  WriterType::Pointer      writer =  WriterType::New();
> >  CastFilterType::Pointer  caster =  CastFilterType::New();
> >  writer->SetFileName(outImageName);
> >  caster->SetInput(resample->GetOutput());
> >  writer->SetInput(caster->GetOutput());
> >  writer->Update();
> > _______________________________________________
> > Insight-users mailing list
> > Insight-users at itk.org
> > http://www.itk.org/mailman/listinfo/insight-users
> >
>
>
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