[Insight-users] Image Intensities Changed During DICOM Read-Write-Read in ITK 3.20 vs. ITK 4.4.1

Bill Lorensen bill.lorensen at gmail.com
Mon Aug 12 14:38:12 EDT 2013


I just tried your code on two different dicom datasets, a ct and an mr.

Both worked for me.
./DICOMTest ~/Data/itkTestcases/Back\ to\ Front/ .
ITK Version: 4.5
Stats for file: /home/lorensen/Data/itkTestcases/Back to
Front//i24389.MRDC.34
Min: 0, Max: 293, Mean: 28.7654, Sigma: 37.2513, Variance: 1387.66, Sum:
1.88517e+06
Stats for file: ./file00.dcm
Min: 0, Max: 293, Mean: 28.7654, Sigma: 37.2513, Variance: 1387.66, Sum:
1.88517e+06
[build] ./DICOMTest ~/Data/NAV/CT/ ./
ITK Version: 4.5
Stats for file: /home/lorensen/Data/NAV/CT//ct.1
Min: -1024, Max: 31744, Mean: 6277.24, Sigma: 13249.9, Variance:
1.75559e+08, Sum: 1.64554e+09
Stats for file: .//file00.dcm
Min: -1024, Max: 31744, Mean: 6277.24, Sigma: 13249.9, Variance:
1.75559e+08, Sum: 1.64554e+09




On Mon, Aug 12, 2013 at 11:46 AM, Constantine Zakkaroff <mnkz at leeds.ac.uk>wrote:

> Hi Brad,
>
> Yes, here's the minimal code:
>
> ****************************************************************
> ************
> #include <cstdlib>
> #include <itkImage.h>
> #include <itkMetaImageIO.h>
> #include <itkGDCMImageIO.h>
> #include <itkGDCMSeriesFileNames.h>
> #include <itkImageFileReader.h>
> #include <itkImageFileWriter.h>
> #include <itkStatisticsImageFilter.h>
>
> int main(int argc, char *argv[])
> {
>         std::clog << "ITK Version: " << ITK_VERSION_STRING << std::endl;
>
>         typedef itk::GDCMSeriesFileNames NamesGeneratorType;
>         typedef itk::Image<short, 3> ImageType;
>
>         NamesGeneratorType::Pointer namesGenerator =
> NamesGeneratorType::New();
>         namesGenerator->**SetUseSeriesDetails(true);
>         namesGenerator->**SetInputDirectory(argv[1]);
>
>         typedef itk::StatisticsImageFilter<**ImageType> StatsFilterType;
>         typedef itk::ImageFileReader<**ImageType> ImageReaderType;
>         typedef itk::ImageFileWriter<**ImageType> ImageWriterType;
>
>         ImageReaderType::Pointer imageReader0 = ImageReaderType::New();
>         imageReader0->SetImageIO(itk::**GDCMImageIO::New());
>         StatsFilterType::Pointer statsFilter0 = StatsFilterType::New();
>         imageReader0->SetFileName(**namesGenerator->**
> GetInputFileNames()[0]);
>         statsFilter0->SetInput(**imageReader0->GetOutput());
>         statsFilter0->Update();
>
>         std::clog << "Stats for file: " << namesGenerator->**GetInputFileNames()[0]
> << std::endl;
>         std::clog <<
>                 "Min: " << statsFilter0->GetMinimum() << ", "
>                 "Max: " << statsFilter0->GetMaximum() << ", "
>                 "Mean: " << statsFilter0->GetMean() << ", "
>                 "Sigma: " << statsFilter0->GetSigma() << ", "
>                 "Variance: " << statsFilter0->GetVariance() << ", "
>                 "Sum: " << statsFilter0->GetSum()
>                 << std::endl;
>
>         ImageWriterType::Pointer imageWriter0 = ImageWriterType::New();
>         imageWriter0->SetInput(**imageReader0->GetOutput());
>         imageWriter0->SetImageIO(itk::**GDCMImageIO::New());
>         std::string fileName0 = std::string(argv[2]) + "/file00.dcm";
>         imageWriter0->SetFileName(**fileName0);
>         imageWriter0->Update();
>
>         ImageReaderType::Pointer imageReader1 = ImageReaderType::New();
>         imageReader1->SetImageIO(itk::**GDCMImageIO::New());
>         StatsFilterType::Pointer statsFilter1 = StatsFilterType::New();
>         imageReader1->SetFileName(**fileName0);
>         statsFilter1->SetInput(**imageReader1->GetOutput());
>         statsFilter1->Update();
>
>         std::clog << "Stats for file: " << fileName0 << std::endl;
>         std::clog <<
>                 "Min: " << statsFilter1->GetMinimum() << ", "
>                 "Max: " << statsFilter1->GetMaximum() << ", "
>                 "Mean: " << statsFilter1->GetMean() << ", "
>                 "Sigma: " << statsFilter1->GetSigma() << ", "
>                 "Variance: " << statsFilter1->GetVariance() << ", "
>                 "Sum: " << statsFilter1->GetSum()
>                 << std::endl;
>
>         system("pause");
>
>         return EXIT_SUCCESS;
> }
> ****************************************************************
> ************
>
> Many thanks,
> Constantine
>
>
> On 12/08/2013 14:48, Bradley Lowekamp wrote:
>
>>
>> Do you have the code to share so that it can be easily reproduced?
>>
>>
>> Thanks,
>> Brad
>>
>> On Aug 12, 2013, at 9:33 AM, Constantine Zakkaroff <mnkz at leeds.ac.uk>
>> wrote:
>>
>>  Hello ALL,
>>>
>>> I'm wondering if anyone can explain what's going on with the changing
>>> image intensities in a read-write-read round-trip. I think it's a bug, but
>>> the issues.itk.org is unresponsive at the moment. Another bug? ;)
>>>
>>> Anyhow, the strange thing is that the results for the round trip
>>> read-write-read test are very different for ITK 3.20 and ITK 4.4.1.
>>>
>>> I use to StatisticsImageFilter to examine the intensity values. Here's
>>> what happens, when I simply read a DICOM image, print stats, save the image
>>> and read it again, followed by printing the stats:
>>>
>>> ITK Version: 3.20
>>> Stats for original file:
>>> Min: 0, Max: 2474, Mean: 169.236, Sigma: 256.719, Variance: 65904.7,
>>> Sum: 1.40371e+007
>>> Stats for saved file:
>>> Min: 0, Max: 2471, Mean: 167.132, Sigma: 256.125, Variance: 65600.1,
>>> Sum: 1.38626e+007
>>>
>>> ITK Version: 4.4
>>> Stats for original file:
>>> Min: 0, Max: 2474, Mean: 169.236, Sigma: 256.719, Variance: 65904.7,
>>> Sum: 1.40371e+007
>>> Stats for saved file:
>>> Min: 0, Max: 7446, Mean: 509.114, Sigma: 772.59, Variance: 596895, Sum:
>>> 4.22279e+007
>>>
>>> In both cases the code is identical. Just compiled against different
>>> versions of ITK. The images are read and written as itk::Image<unsigned
>>> short, 3>, with no processing, no changes to any aspect of the images.
>>>
>>> So, ITK 3.20 introduces a small change, which I'm pretty sure shouldn't
>>> be there. But in ITK 4.4.1 the scale of intensities changes three-fold.
>>>
>>> I'd not be surprised by a change of this magnitude if I was photocopying
>>> those images, but not when using digital software and hardware. :^) Is
>>> there something I'm not understanding here?
>>>
>>> None of this happens with read(DICOM)-write(MHD)-read(**MHD), where the
>>> original and round-trip values are identical:
>>> Stats for saved file: file0.mhd
>>> Min: 0, Max: 2474, Mean: 169.236, Sigma: 256.719, Variance: 65904.7,
>>> Sum: 1.40371e+007
>>>
>>> Many thanks,
>>> Constantine
>>>
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