diff --git a/Code/BasicFilters/otbConvolutionImageFilter.txx b/Code/BasicFilters/otbConvolutionImageFilter.txx
index 36195614b96aa42c01d58c7d9a5dd58cd0710ab3..e326da53e6241672a841e6966435f903ab7a76ae 100644
--- a/Code/BasicFilters/otbConvolutionImageFilter.txx
+++ b/Code/BasicFilters/otbConvolutionImageFilter.txx
@@ -137,11 +137,9 @@ ConvolutionImageFilter< TInputImage, TOutputImage, TBoundaryCondition>
       norm = itk::NumericTraits<InputRealType>::Zero;
       for (i = 0; i < neighborhoodSize; ++i)
 	{
-	 norm += static_cast<InputRealType>( m_Filter(i)*m_Filter(i) );
+	 norm += static_cast<InputRealType>( m_Filter(i) );
 	}
-      norm = vcl_sqrt(norm);
       }
-    
 
     while ( ! bit.IsAtEnd() )
     {