[Insight-users] Bug in OtsuThresholdImageFilter?

[Frederic Perez]

Hello Roman,

On Thu, Aug 19, 2010 at 2:45 PM, Roman Grothausmann <
roman.grothausmann at helmholtz-berlin.de> wrote:

> Dear mailing list members,
>
>
> GetThreshold() from OtsuThresholdImageFilter in the code below does not
> return any value. Is that a bug?
>

According to the documentation (
http://www.itk.org/Doxygen320/html/classitk_1_1OtsuThresholdImageFilter.html#a7c5fd26660c92354986d61ff8770cf86
),

template<class TInputImage , class TOutputImage >
virtual InputPixelType<http://www.itk.org/Doxygen320/html/classitk_1_1OtsuThresholdImageFilter.html#a3495c875550c2ae4ed950ef5e54567a1>
 itk::OtsuThresholdImageFilter<http://www.itk.org/Doxygen320/html/classitk_1_1OtsuThresholdImageFilter.html><
TInputImage, TOutputImage >::GetThreshold (  ) const [virtual]

you should get an InputPixelType. Since you have instantiated unsigned chars,
perhaps you are getting a character that doesn't "show up."

Try debugging, or do something like

std::cout << "Threshold: " << static_cast<unsigned
int>(filter->GetThreshold()) << std::endl;


Regards,

Frederic Perez


> Any help is very much appreciated
> Roman
>
>
> ________________________________________
>
> #include <itkImageFileReader.h>
> #include <itkImageFileWriter.h>
>
> #include <itkOtsuThresholdImageFilter.h>
> #include "itkFilterWatcher2.h"
>
> int main( int argc, char * argv[] )
>    {
>    if( argc != 4 )
>        {
>        std::cerr << "Usage: " << argv[0];
>        std::cerr << " inputImage";
>        std::cerr << " outputImage";
>        std::cerr << " #_of_hist-bins";
>        std::cerr << std::endl;
>        return EXIT_FAILURE;
>        }
>
>    typedef  unsigned char InputPixelType;
>    typedef  unsigned char OutputPixelType;
>
>    const unsigned int Dimension = 3;
>
>    typedef itk::Image<InputPixelType,  Dimension>   InputImageType;
>    typedef itk::Image<OutputPixelType,  Dimension>   OutputImageType;
>
>    typedef itk::ImageFileReader<InputImageType>  ReaderType;
>    typedef itk::ImageFileWriter<OutputImageType>  WriterType;
>    WriterType::Pointer writer = WriterType::New();
>
>    ReaderType::Pointer reader = ReaderType::New();
>    reader->SetFileName(argv[1]);
>
>    typedef itk::OtsuThresholdImageFilter<InputImageType, OutputImageType>
> FilterType;
>    FilterType::Pointer filter = FilterType::New();
>
>
>    filter->SetNumberOfHistogramBins(atoi(argv[3]));
>
>    filter->SetInput(reader->GetOutput());
>    FilterWatcher watcher(filter, "filter");
>    filter->Update();
>
>    std::cout << "Threshold: " << filter->GetThreshold() << std::endl;
>
>    writer->SetFileName(argv[2]);
>    writer->SetInput(filter->GetOutput());
>    writer->Update();
>
>    return EXIT_SUCCESS;
>    }
>
>
>
>
> --
> Roman Grothausmann
>
> Helmholtz-Zentrum Berlin für Materialien und Energie GmbH
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