diff --git a/Code/IO/otbDEMToImageGenerator.h b/Code/IO/otbDEMToImageGenerator.h
index b3b8c703049521933bd21aa5a5c628c2e048d7e9..950b7b6c49cd4c7afa09bbe3c04095a6dd378dbf 100644
--- a/Code/IO/otbDEMToImageGenerator.h
+++ b/Code/IO/otbDEMToImageGenerator.h
@@ -99,10 +99,6 @@ public:
   itkSetMacro(OutputSpacing, SpacingType);
   itkGetConstReferenceMacro(OutputSpacing, SpacingType);
 
-  /** Set/Get the Default Unknown Value. */
-  itkSetMacro(DefaultUnknownValue, PixelType);
-  itkGetConstReferenceMacro(DefaultUnknownValue, PixelType);
-
   /** Set/Get the Default Unknown Value. */
   itkSetObjectMacro(Transform, GenericRSTransformType);
   itkGetObjectMacro(Transform, GenericRSTransformType);
@@ -116,7 +112,6 @@ public:
   itkSetObjectMacro(DEMFunction, DEMFunctionBaseType);
   itkGetConstObjectMacro(DEMFunction, DEMFunctionBaseType);
 
-
   /**
    * Set/Get input & output projections.
    * Set/Get input & output keywordlist
@@ -192,8 +187,6 @@ protected:
   PointType               m_OutputOrigin;
   SpacingType             m_OutputSpacing;
   SizeType                m_OutputSize;
-  PixelType               m_DefaultUnknownValue;
-
   DEMFunctionBasePointer  m_DEMFunction;
 
 private:
diff --git a/Code/IO/otbDEMToImageGenerator.txx b/Code/IO/otbDEMToImageGenerator.txx
index e4c0128a1cfd8b8e09245ef1937d19ff6b14a11f..4f76660bf0efc94849f04420d96ae8bf03b921dd 100644
--- a/Code/IO/otbDEMToImageGenerator.txx
+++ b/Code/IO/otbDEMToImageGenerator.txx
@@ -38,6 +38,8 @@ DEMToImageGenerator<TDEMImage>
   m_OutputOrigin[1] = 0;
 
   m_Transform         = GenericRSTransformType::New();
+  m_DEMFunction       = SRTMFunctionType::New();
+
 }
 
 // DEM folder specification method