<div dir="ltr"><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><span style="font-family:arial,sans-serif;font-size:12.8000001907349px">Joint PDF summed to zero is usually triggered when the images you are trying to register do not overlap. I guess the first issue is caused by this too. You should have better initialization. At least translate the images enough so the partly overlap.</span><br></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><span style="font-family:arial,sans-serif;font-size:12.8000001907349px"><br></span></div><div class="gmail_default" style="font-family:verdana,sans-serif;font-size:small"><span style="font-family:arial,sans-serif;font-size:12.8000001907349px">HTH</span></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Aug 18, 2015 at 10:08 AM, Constantinus Spanakis <span dir="ltr"><<a href="mailto:c.spanakis83@gmail.com" target="_blank">c.spanakis83@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello, i tried to modify the example  DeformableRegistration15.cxx by<br>
replacing the Regular step gradient Descent optimizer with One plus<br>
One optimizer. At first i had problem with having too many samples<br>
outside moving image buffer. I corrected that problem by reducing the<br>
number of spatial samples. Then i got this problem:<br>
<br>
itk::ExceptionObject (00000000002FE348)<br>
Location: "double __cdecl itk::MattesMutualInformationImageToImageMetric<class i<br>
tk::Image<short,3>,class itk::Image<short,3> >::GetValue(const class itk::Optimi<br>
zerParameters<double> &) const"<br>
File: c:\itk\modules\registration\common\include\itkMattesMutualInformationImage<br>
ToImageMetric.hxx<br>
Line: 571<br>
Description: itk::ERROR: MattesMutualInformationImageToImageMetric(00000000027FA<br>
FF0): Joint PDF summed to zero<br>
Image (0000000002815040)<br>
  RTTI typeinfo:   class itk::Image<double,2><br>
  Reference Count: 2<br>
  Modified Time: 462<br>
  Debug: Off<br>
  Object Name:<br>
  Observers:<br>
    none<br>
  Source: (none)<br>
  Source output name: (none)<br>
  Release Data: Off<br>
  Data Released: False<br>
  Global Release Data: Off<br>
  PipelineMTime: 0<br>
  UpdateMTime: 0<br>
  RealTimeStamp: 0 seconds<br>
  LargestPossibleRegion:<br>
    Dimension: 2<br>
    Index: [0, 0]<br>
    Size: [50, 50]<br>
  BufferedRegion:<br>
    Dimension: 2<br>
    Index: [0, 0]<br>
    Size: [50, 50]<br>
  RequestedRegion:<br>
    Dimension: 2<br>
    Index: [0, 0]<br>
    Size: [50, 50]<br>
  Spacing: [83.0652, 46.913]<br>
  Origin: [2, 2]<br>
  Direction:<br>
1 0<br>
0 1<br>
<br>
  IndexToPointMatrix:<br>
83.0652 0<br>
0 46.913<br>
<br>
  PointToIndexMatrix:<br>
0.0120387 0<br>
0 0.021316<br>
<br>
  Inverse Direction:<br>
1 0<br>
0 1<br>
<br>
  PixelContainer:<br>
    ImportImageContainer (0000000002777D40)<br>
      RTTI typeinfo:   class itk::ImportImageContainer<unsigned long,double><br>
      Reference Count: 1<br>
      Modified Time: 463<br>
      Debug: Off<br>
      Object Name:<br>
      Observers:<br>
        none<br>
      Pointer: 0000000002911380<br>
      Container manages memory: true<br>
      Size: 2500<br>
      Capacity: 2500<br>
<br>
Could someone please explain the problem more analytically and help me solve it?<br>
<br>
Thank you<br>
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</blockquote></div><br></div>