ENH : Adapt margin according size image into SARDEMPolygonsAnalysis filter

include/otbSARDEMPolygonsAnalysisImageFilter.txx

@@ -179,10 +179,14 @@ namespace otb
     // Set the margin
     int nbLinesSAR = m_SarImagePtr->GetLargestPossibleRegion().GetSize()[1];
     int nbLinesDEM = m_DemImagePtr->GetLargestPossibleRegion().GetSize()[1];
-    if (nbLinesSAR > nbLinesDEM)
+    if (nbLinesSAR/2 > nbLinesDEM)
       { 
 	m_Margin = (nbLinesSAR/nbLinesDEM)*30;
       }
+    else if (nbLinesSAR > nbLinesDEM)
+      {
+	m_Margin = (nbLinesSAR/nbLinesDEM)*60;
+      }
     else
       {
 	m_Margin = 100;