From: Simon Rit <simon.rit@creatis.insa-lyon.fr>
Date: Wed, 24 Jul 2013 11:29:54 +0000 (+0200)
Subject: When resampling, keeping the same origin seems wrong because the origin
X-Git-Tag: v1.4.0~2^2~8^2~1
X-Git-Url: https://git.creatis.insa-lyon.fr/pubgit/?a=commitdiff_plain;h=ae2fd017cec9dc939c314e49718abcdad161968c;p=clitk.git

When resampling, keeping the same origin seems wrong because the origin
is not the corner of the image but the center of the first pixel
---

diff --git a/itk/clitkResampleImageWithOptionsFilter.txx b/itk/clitkResampleImageWithOptionsFilter.txx
index a3f88be..ddaa8a0 100644
--- a/itk/clitkResampleImageWithOptionsFilter.txx
+++ b/itk/clitkResampleImageWithOptionsFilter.txx
@@ -222,12 +222,19 @@ GenerateData()
     std::cout << "LastDimIsTime  = " << m_LastDimensionIsTime << std::endl;
   }
 
+  // Compute origin based on image corner
+  typename FilterType::OriginPointType origin = input->GetOrigin();
+  for(unsigned int i=0; i<OutputImageType::ImageDimension; i++) {
+    origin[i] -= 0.5 * input->GetSpacing()[i];
+    origin[i] += 0.5 * m_OutputSpacing[i];
+  }
+
   // Instance of the transform object to be passed to the resample
   // filter. By default, identity transform is applied
   filter->SetTransform(m_Transform);
   filter->SetSize(m_OutputSize);
   filter->SetOutputSpacing(m_OutputSpacing);
-  filter->SetOutputOrigin(input->GetOrigin());
+  filter->SetOutputOrigin(origin);
   filter->SetDefaultPixelValue(m_DefaultPixelValue);
   filter->SetNumberOfThreads(this->GetNumberOfThreads()); 
   filter->SetOutputDirection(input->GetDirection()); // <-- NEEDED if we want to keep orientation (in case of PermutAxes for example)