[ITK-users] [ITK] ImageToImageMetric in Python

[Prevrhal, Sven]

Thanks Matt and Jagjeet,
It's better but still not working correctly. Here's what I have now:



       metricType = itk.NormalizedCorrelationImageToImageMetric.IF3IF3
        transformType = itk.TranslationTransform.D3
        interpolatorType = itk.LinearInterpolateImageFunction.IF3D
        fixedImage = files['T2']['itkImage'] # I checked, data are fine

        metric = metricType.New()
        tr = transformType.New()
        ip = interpolatorType.New()

        metric.SetTransform(tr)
        tr.SetIdentity()
        metric.SetInterpolator(ip)
        metric.SetFixedImage(fixedImage)

        # metric.GetFixedImageRegion() is [0,0,0], [0,0,0] without a line like:
        #metric.SetFixedImageRegion( fixedImage.GetBufferedRegion() )
        metric.SetFixedImageRegion(  itk.ImageRegion._3([0,0,0],[10,10,10]) )

        zeroDisplacement = itk.OptimizerParameters.D(3)
        for i,v in enumerate([0,0,0]): zeroDisplacement.SetElement(i,v)

        movingImage = files[typ]['itkImage']   # data are fine and different from fixedImage
        metric.SetMovingImage(movingImage)
        v = metric.GetValue(zeroDisplacement)
        print 'NCC T2 - %s: %f' % (typ, v)



The code crashes without error message at the GetValue call. If I drop the SetFixedImageRegion, it does run but produces v=0.0 no matter what. Any more insight would be greatly appreciated.

Kind regards,
Sven

-----Original Message-----
From: Matt McCormick [mailto:matt.mccormick at kitware.com]
Sent: Dienstag, 8. April 2014 20:10
To: Prevrhal, Sven
Cc: insight-users at itk.org
Subject: Re: [ITK] [ITK-users] ImageToImageMetric in Python

Hi Sven,

To find the type of MetricType::TransformParametersType, look at the Doxygen documentation for NormalizedCorrelationImageToImageMetric [1].
 Following the typedef trail [2], the type is OptimizerParameters [3], which can be created with

  displacement = itk.OptimizerParameters.F( Dimension )

Hope this helps,
Matt

[1] http://www.itk.org/Doxygen/html/classitk_1_1NormalizedCorrelationImageToImageMetric.html

[2] http://www.itk.org/Doxygen/html/classitk_1_1TransformBaseTemplate.html

[3] http://www.itk.org/Doxygen/html/classitk_1_1OptimizerParameters.html

On Tue, Apr 8, 2014 at 1:34 PM, Prevrhal, Sven <Sven.Prevrhal at philips.com> wrote:
> I am looking at the itk Software Guide to figure out how to implement
> this in Python. I have:
>
>
>
>         nccMetric =
> itk.NormalizedCorrelationImageToImageMetric.IF3IF3.New()
>
>         nccMetric.SetTransform(itk.IdentityTransform.D3.New())
>
>
> nccMetric.SetInterpolator(itk.NearestNeighborInterpolateImageFunction.
> IF3D.New())
>
>         nccMetric.SetFixedImage(fixedImage)
>
>         nccMetric.SetMovingImage(movingImage)
>
>
>
> which I believe works fine. I am getting stumped by the translation of
> this to Python:
>
>
>
>   # ITK software guide page 390
>
>   # C++ code: MetricType::TransformParametersType displacement(
> Dimension );
>
>         displacement = nccMetric.??
>
>
>
> After which
>
>
>
> value = nccMetric.GetValue( displacement )
>
>
>
> should work fine. Anybody knows this?
>
>
>
> Regards,
>
> Sven
>
>
>
> Sven Prevrhal
>
> Philips Research
>
>
>
>
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The information contained in this message may be confidential and legally protected under applicable law. The message is intended solely for the addressee(s). If you are not the intended recipient, you are hereby notified that any use, forwarding, dissemination, or reproduction of this message is strictly prohibited and may be unlawful. If you are not the intended recipient, please contact the sender by return e-mail and destroy all copies of the original message.