diff --git a/modules/tracker/rbt/include/visp3/rbt/vpColorHistogram.h b/modules/tracker/rbt/include/visp3/rbt/vpColorHistogram.h
index 92ed08d20e..ad51c29b91 100644
--- a/modules/tracker/rbt/include/visp3/rbt/vpColorHistogram.h
+++ b/modules/tracker/rbt/include/visp3/rbt/vpColorHistogram.h
@@ -87,7 +87,7 @@ class VISP_EXPORT vpColorHistogram
 
   void build(const vpImage<vpRGBa> &image, const vpImage<bool> &mask);
 
-  void build(std::vector<unsigned int> &counts);
+  void build(const std::vector<unsigned int> &counts);
 
   void merge(const vpColorHistogram &other, float alpha);
 
diff --git a/modules/tracker/rbt/include/visp3/rbt/vpRBFeatureTrackerFactory.h b/modules/tracker/rbt/include/visp3/rbt/vpRBFeatureTrackerFactory.h
index 320db68570..094c99a08f 100644
--- a/modules/tracker/rbt/include/visp3/rbt/vpRBFeatureTrackerFactory.h
+++ b/modules/tracker/rbt/include/visp3/rbt/vpRBFeatureTrackerFactory.h
@@ -49,9 +49,9 @@ class VISP_EXPORT vpRBFeatureTrackerFactory : public vpDynamicFactory<vpRBFeatur
 {
 private:
   vpRBFeatureTrackerFactory();
-  virtual ~vpRBFeatureTrackerFactory() = default;
 
 public:
+  virtual ~vpRBFeatureTrackerFactory() = default;
   static vpRBFeatureTrackerFactory &getFactory()
   {
     static vpRBFeatureTrackerFactory factory;
diff --git a/modules/tracker/rbt/src/mask/vpColorHistogram.cpp b/modules/tracker/rbt/src/mask/vpColorHistogram.cpp
index 48e0304b38..b992614092 100644
--- a/modules/tracker/rbt/src/mask/vpColorHistogram.cpp
+++ b/modules/tracker/rbt/src/mask/vpColorHistogram.cpp
@@ -94,7 +94,7 @@ void vpColorHistogram::build(const vpImage<vpRGBa> &image, const vpImage<bool> &
   }
 }
 
-void vpColorHistogram::build(std::vector<unsigned int> &counts)
+void vpColorHistogram::build(const std::vector<unsigned int> &counts)
 {
   if (m_probas.size() != counts.size()) {
     throw vpException(vpException::dimensionError, "Number of bins are not the same");