[Insight-users] Statistic getting frequency of a Value

[Karthik Krishnan]

Once you have created the ListSample, (You would rather use the 
ScalarImageToListAdaptor). Create a histogram with two bins and the 
frequency of second bin would be what you want, something like:


  typedef itk::Statistics::ListSampleToHistogramGenerator< 
ListSampleType, float > GeneratorType;
  GeneratorType::Pointer generator = GeneratorType::New();
  GeneratorType::HistogramType::SizeType size;
  size.Fill(2);
  generator->SetListSample( listsample );
  generator->SetNumberOfBins( size );
  generator->SetMarginalScale( 10.0 );
  generator->Update();
  GeneratorType::HistogramType::ConstPointer histogram = 
generator->GetOutput();
  GeneratorType::HistogramType::ConstIterator iter = histogram->Begin();
  while ( iter != histogram->End() )
    {
    std::cout << " frequency = " << iter.GetFrequency() << std::endl;
    ++iter;
    }



Bradley Lowekamp wrote:

>
> I have some images that are binary like, with values of 0 and 255. I 
> want to count the number (or frequency of a specific value). I have 
> created a ImageToListAdaptor converting my pixel type to a fixed 
> array. I want to count the number of pixels that have a value of say 
> 255. How do I do this?
>
>
> Thanks,
> Brad
>
> ========================================================
> Bradley Lowekamp
> Management Systems Designers Contractor for
> Office of High Performance Computing and Communications
> National Library of Medicine
> 'blowekamp at mail.nih.gov
>
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