[Insight-developers] Bug in itkSignedMaurerDistanceMapImageFilter class

[Nicholas Tustison]

Hi Luis,

I found a bug in the itkSignedMaurerDistanceMapImageFilter class.   
Since I was the contributing author, I feel like I owe somebody (or  
perhaps the ITK masses) an apology.  Anyway, the code throws an  
exception when the requested region has non-zero index values.  The  
fix requires the four changes given below to take into account non- 
zero index values.  I don't remember if the freeze is still in place  
which is why I'm sending the fixes to you.

Thanks,
Nick Tustison

1. Current version 1.4 (lines 175-176):

   InputRegionType region = this->GetInput()->GetRequestedRegion();
   InputSizeType   size   = region.GetSize();

Proposed fix:

   InputRegionType region = this->GetInput()->GetRequestedRegion();
   InputSizeType   size   = region.GetSize();
   typename InputImageType::RegionType::IndexType startIndex;
   startIndex = this->GetInput()->GetRequestedRegion().GetIndex();


2. Current version 1.4 (lines 210-213):

         idx[ d % InputImageDimension ] =
              static_cast<unsigned int>(
                  static_cast<double>( index ) /
                  static_cast<double>( k[count] ) );


Proposed fix:

         idx[ d % InputImageDimension ] =
              static_cast<unsigned int>(
                  static_cast<double>( index ) /
                  static_cast<double>( k[count] ) )
              + startIndex[ d % InputImageDimension ];

3. Current version 1.4 (lines 285-294)

   vnl_vector<OutputPixelType> g(nd);  g = 0;
   vnl_vector<OutputPixelType> h(nd);  h = 0;

   OutputPixelType di;

   int l = -1;

   for( unsigned int i = 0; i < nd; i++ )
     {
     idx[d] = i;


Proposed fix:

   vnl_vector<OutputPixelType> g(nd);  g = 0;
   vnl_vector<OutputPixelType> h(nd);  h = 0;

   typename InputImageType::RegionType::IndexType startIndex;
   startIndex = this->GetInput()->GetRequestedRegion().GetIndex();

   OutputPixelType di;

   int l = -1;

   for( unsigned int i = 0; i < nd; i++ )
     {
     idx[d] = i + startIndex[d];

4. Current version 1.4 (line 363)

     idx[d] = i;

Proposed Fix:

     idx[d] = i + startIndex[d];


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