diff --git a/Modules/Filtering/DisplacementField/include/itkTimeVaryingVelocityFieldIntegrationImageFilter.hxx b/Modules/Filtering/DisplacementField/include/itkTimeVaryingVelocityFieldIntegrationImageFilter.hxx
index 7b90bbee857..8432264d3ec 100644
--- a/Modules/Filtering/DisplacementField/include/itkTimeVaryingVelocityFieldIntegrationImageFilter.hxx
+++ b/Modules/Filtering/DisplacementField/include/itkTimeVaryingVelocityFieldIntegrationImageFilter.hxx
@@ -64,11 +64,11 @@ TimeVaryingVelocityFieldIntegrationImageFilter<TTimeVaryingVelocityField,
 {
   const TimeVaryingVelocityFieldType * input = this->GetInput();
   DisplacementFieldType *              output = this->GetOutput();
-  this->m_NumberOfTimePoints = input->GetLargestPossibleRegion().GetSize()[OutputImageDimension];
   if (!input || !output)
   {
     return;
   }
+  this->m_NumberOfTimePoints = input->GetLargestPossibleRegion().GetSize()[OutputImageDimension];
 
   //
   // The ImageBase::CopyInformation() method ca not be used here