diff --git a/modules/tracker/klt/CMakeLists.txt b/modules/tracker/klt/CMakeLists.txt
index f001ed5962..1540315835 100644
--- a/modules/tracker/klt/CMakeLists.txt
+++ b/modules/tracker/klt/CMakeLists.txt
@@ -37,6 +37,11 @@
 set(opt_incs "")
 set(opt_libs "")
 
+if(USE_NLOHMANN_JSON AND NOT VISP_HAVE_NLOHMANN_JSON_FROM_VTK)
+  get_target_property(_inc_dirs "nlohmann_json::nlohmann_json" INTERFACE_INCLUDE_DIRECTORIES)
+  list(APPEND opt_incs ${_inc_dirs})
+endif()
+
 # OpenCV
 if(USE_OPENCV)
   # On win32 since OpenCV 2.4.7 and on OSX with OpenCV 2.4.10 we cannot use OpenCV_LIBS to set ViSP 3rd party libraries.
diff --git a/modules/tracker/klt/include/visp3/klt/vpKltOpencv.h b/modules/tracker/klt/include/visp3/klt/vpKltOpencv.h
index 60a8078eea..d9bde51eeb 100644
--- a/modules/tracker/klt/include/visp3/klt/vpKltOpencv.h
+++ b/modules/tracker/klt/include/visp3/klt/vpKltOpencv.h
@@ -267,7 +267,7 @@ class VISP_EXPORT vpKltOpencv
    * However, it must be a positive integer.
    *
    * \param blockSize : Size of an average block for computing a derivative
-   * covariation matrix over each pixel neighborhood. Default value is set to 3.
+   * covariance matrix over each pixel neighborhood. Default value is set to 3.
    */
   void setBlockSize(int blockSize) { m_blockSize = blockSize; }
 
diff --git a/modules/visual_features/src/visual-feature/vpFeatureMomentGravityCenterNormalized.cpp b/modules/visual_features/src/visual-feature/vpFeatureMomentGravityCenterNormalized.cpp
index 193687eb04..d561693847 100644
--- a/modules/visual_features/src/visual-feature/vpFeatureMomentGravityCenterNormalized.cpp
+++ b/modules/visual_features/src/visual-feature/vpFeatureMomentGravityCenterNormalized.cpp
@@ -45,6 +45,7 @@
 #include <visp3/visual_features/vpFeatureMomentDatabase.h>
 #include <visp3/visual_features/vpFeatureMomentGravityCenter.h>
 #include <visp3/visual_features/vpFeatureMomentGravityCenterNormalized.h>
+
 BEGIN_VISP_NAMESPACE
 /*!
  * Computes interaction matrix for centered and normalized moment. Called