diff --git a/Modules/Learning/Sampling/include/otbSampleAugmentation.h b/Modules/Learning/Sampling/include/otbSampleAugmentation.h
index 432dbe8a26090422f6b0833678bf2b0ba327c039..b778e79f26172d383106d8e05b6662a6fab78357 100644
--- a/Modules/Learning/Sampling/include/otbSampleAugmentation.h
+++ b/Modules/Learning/Sampling/include/otbSampleAugmentation.h
@@ -164,7 +164,7 @@ void findKNNIndices(const SampleVectorType& inSamples,
 
 /** Generate the new sample in the line linking s1 and s2
 */
-SampleType smoteCombine(SampleType s1, SampleType s2, double position)
+SampleType smoteCombine(const SampleType& s1, const SampleType& s2, double position)
 {
   auto result = s1;
   for(size_t i=0; i<s1.size(); ++i)