diff --git a/include/otbStreamingGraphToImageFilter.txx b/include/otbStreamingGraphToImageFilter.txx
index 0332f547bf63ae56813caca4989eb8f0da2d955c..431f7d94a444861d65ab024a0472cfe1c536edeb 100644
--- a/include/otbStreamingGraphToImageFilter.txx
+++ b/include/otbStreamingGraphToImageFilter.txx
@@ -135,7 +135,7 @@ StreamingGraphToImageFilter<TGraph, TLabelImage>
 		  try {
           index[0] = (unsigned int)(pix % (std::size_t)(m_OutputSize[0]));
           index[1] = (unsigned int)(pix / (std::size_t)(m_OutputSize[0]));
-          labelImage->SetPixel(index, res.second);
+          labelImage->SetPixel(index, res.second + 1);
 		  } catch (std::exception e) {
 			  std::cout << "Pixel ID: " << pix << std::endl;
 			  std::cout << "Derived index: " << index[0] << "," << index[1] << std::endl;