diff --git a/modules/flann/include/opencv2/flann/all_indices.h b/modules/flann/include/opencv2/flann/all_indices.h
index b1a826f764..865ca53ae9 100644
--- a/modules/flann/include/opencv2/flann/all_indices.h
+++ b/modules/flann/include/opencv2/flann/all_indices.h
@@ -27,8 +27,8 @@
  *************************************************************************/
 
 
-#ifndef ALL_INDICES_H_
-#define ALL_INDICES_H_
+#ifndef _OPENCV_ALL_INDICES_H_
+#define _OPENCV_ALL_INDICES_H_
 
 #include "opencv2/flann/general.h"
 
@@ -73,4 +73,4 @@ NNIndex<T>* create_index_by_type(const Matrix<T>& dataset, const IndexParams& pa
 
 } //namespace cvflann
 
-#endif /* ALL_INDICES_H_ */
+#endif /* _OPENCV_ALL_INDICES_H_ */
diff --git a/modules/flann/include/opencv2/flann/allocator.h b/modules/flann/include/opencv2/flann/allocator.h
index fca88d681d..cc571e4602 100644
--- a/modules/flann/include/opencv2/flann/allocator.h
+++ b/modules/flann/include/opencv2/flann/allocator.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef ALLOCATOR_H
-#define ALLOCATOR_H
+#ifndef _OPENCV_ALLOCATOR_H_
+#define _OPENCV_ALLOCATOR_H_
 
 #include <stdlib.h>
 #include <stdio.h>
@@ -184,4 +184,4 @@ public:
 
 } // namespace cvflann
 
-#endif //ALLOCATOR_H
+#endif //_OPENCV_ALLOCATOR_H_
diff --git a/modules/flann/include/opencv2/flann/autotuned_index.h b/modules/flann/include/opencv2/flann/autotuned_index.h
index 0d32e398fc..8a9b724983 100644
--- a/modules/flann/include/opencv2/flann/autotuned_index.h
+++ b/modules/flann/include/opencv2/flann/autotuned_index.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef AUTOTUNEDINDEX_H_
-#define AUTOTUNEDINDEX_H_
+#ifndef _OPENCV_AUTOTUNEDINDEX_H_
+#define _OPENCV_AUTOTUNEDINDEX_H_
 
 #include "opencv2/flann/general.h"
 #include "opencv2/flann/nn_index.h"
@@ -611,4 +611,4 @@ private:
 
 } // namespace cvflann
 
-#endif /* AUTOTUNEDINDEX_H_ */
+#endif /* _OPENCV_AUTOTUNEDINDEX_H_ */
diff --git a/modules/flann/include/opencv2/flann/composite_index.h b/modules/flann/include/opencv2/flann/composite_index.h
index 24bc640558..dfcfab5153 100644
--- a/modules/flann/include/opencv2/flann/composite_index.h
+++ b/modules/flann/include/opencv2/flann/composite_index.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef COMPOSITETREE_H
-#define COMPOSITETREE_H
+#ifndef _OPENCV_COMPOSITETREE_H_
+#define _OPENCV_COMPOSITETREE_H_
 
 #include "opencv2/flann/general.h"
 #include "opencv2/flann/nn_index.h"
@@ -160,4 +160,4 @@ public:
 
 } // namespace cvflann
 
-#endif //COMPOSITETREE_H
+#endif //_OPENCV_COMPOSITETREE_H_
diff --git a/modules/flann/include/opencv2/flann/dist.h b/modules/flann/include/opencv2/flann/dist.h
index 162d89bab8..ef25af9b9b 100644
--- a/modules/flann/include/opencv2/flann/dist.h
+++ b/modules/flann/include/opencv2/flann/dist.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef DIST_H
-#define DIST_H
+#ifndef _OPENCV_DIST_H_
+#define _OPENCV_DIST_H_
 
 #include <cmath>
 using namespace std;
@@ -358,4 +358,4 @@ CV_EXPORTS ZeroIterator<float>& zero();
 
 } // namespace cvflann
 
-#endif //DIST_H
+#endif //_OPENCV_DIST_H_
diff --git a/modules/flann/include/opencv2/flann/flann.hpp b/modules/flann/include/opencv2/flann/flann.hpp
index e3a05204a9..0a9f38ffad 100644
--- a/modules/flann/include/opencv2/flann/flann.hpp
+++ b/modules/flann/include/opencv2/flann/flann.hpp
@@ -40,8 +40,8 @@
 //
 //M*/
 
-#ifndef __OPENCV_FLANN_HPP__
-#define __OPENCV_FLANN_HPP__
+#ifndef _OPENCV_FLANN_HPP_
+#define _OPENCV_FLANN_HPP_
 
 #ifdef __cplusplus
 
diff --git a/modules/flann/include/opencv2/flann/flann_base.hpp b/modules/flann/include/opencv2/flann/flann_base.hpp
index 2189e46ecb..f5e740cef0 100644
--- a/modules/flann/include/opencv2/flann/flann_base.hpp
+++ b/modules/flann/include/opencv2/flann/flann_base.hpp
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef FLANN_HPP_
-#define FLANN_HPP_
+#ifndef _OPENCV_FLANN_BASE_HPP_
+#define _OPENCV_FLANN_BASE_HPP_
 
 #include <vector>
 #include <string>
@@ -258,4 +258,4 @@ int hierarchicalClustering(const Matrix<ELEM_TYPE>& features, Matrix<DIST_TYPE>&
 }
 
 } // namespace cvflann
-#endif /* FLANN_HPP_ */
+#endif /* _OPENCV_FLANN_BASE_HPP_ */
diff --git a/modules/flann/include/opencv2/flann/general.h b/modules/flann/include/opencv2/flann/general.h
index ab2b26dde7..17a84922fc 100644
--- a/modules/flann/include/opencv2/flann/general.h
+++ b/modules/flann/include/opencv2/flann/general.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef OPENCV_CONSTANTS_H
-#define OPENCV_CONSTANTS_H
+#ifndef _OPENCV_GENERAL_H_
+#define _OPENCV_GENERAL_H_
 
 #ifdef __cplusplus
 
@@ -146,4 +146,4 @@ struct CV_EXPORTS SearchParams {
 
 #endif
 
-#endif  /* OPENCV_CONSTANTS_H */
+#endif  /* _OPENCV_GENERAL_H_ */
diff --git a/modules/flann/include/opencv2/flann/ground_truth.h b/modules/flann/include/opencv2/flann/ground_truth.h
index f76f500f8a..155697b7a0 100644
--- a/modules/flann/include/opencv2/flann/ground_truth.h
+++ b/modules/flann/include/opencv2/flann/ground_truth.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef GROUND_TRUTH_H
-#define GROUND_TRUTH_H
+#ifndef _OPENCV_GROUND_TRUTH_H_
+#define _OPENCV_GROUND_TRUTH_H_
 
 #include "opencv2/flann/dist.h"
 #include "opencv2/flann/matrix.h"
@@ -92,4 +92,4 @@ void compute_ground_truth(const Matrix<T>& dataset, const Matrix<T>& testset, Ma
 
 } // namespace cvflann
 
-#endif //GROUND_TRUTH_H
+#endif //_OPENCV_GROUND_TRUTH_H_
diff --git a/modules/flann/include/opencv2/flann/hdf5.h b/modules/flann/include/opencv2/flann/hdf5.h
index 646c6b42d1..727d5a13ac 100644
--- a/modules/flann/include/opencv2/flann/hdf5.h
+++ b/modules/flann/include/opencv2/flann/hdf5.h
@@ -27,8 +27,8 @@
  *************************************************************************/
 
 
-#ifndef IO_H_
-#define IO_H_
+#ifndef _OPENCV_HDF5_H_
+#define _OPENCV_HDF5_H_
 
 #include <H5Cpp.h>
 
@@ -160,4 +160,4 @@ void load_from_file(cvflann::Matrix<T>& flann_dataset, const std::string& filena
 
 } // namespace cvflann
 
-#endif /* IO_H_ */
+#endif /* _OPENCV_HDF5_H_ */
diff --git a/modules/flann/include/opencv2/flann/heap.h b/modules/flann/include/opencv2/flann/heap.h
index d1580173a9..518423fe55 100644
--- a/modules/flann/include/opencv2/flann/heap.h
+++ b/modules/flann/include/opencv2/flann/heap.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef HEAP_H
-#define HEAP_H
+#ifndef _OPENCV_HEAP_H_
+#define _OPENCV_HEAP_H_
 
 
 #include <algorithm>
@@ -206,4 +206,4 @@ public:
 
 } // namespace cvflann
 
-#endif //HEAP_H
+#endif //_OPENCV_HEAP_H_
diff --git a/modules/flann/include/opencv2/flann/index_testing.h b/modules/flann/include/opencv2/flann/index_testing.h
index 04163f2b9d..4acabcf4af 100644
--- a/modules/flann/include/opencv2/flann/index_testing.h
+++ b/modules/flann/include/opencv2/flann/index_testing.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef TESTING_H
-#define TESTING_H
+#ifndef _OPENCV_TESTING_H_
+#define _OPENCV_TESTING_H_
 
 #include <cstring>
 #include <cassert>
@@ -289,4 +289,4 @@ float test_index_precisions(NNIndex<ELEM_TYPE>& index, const Matrix<ELEM_TYPE>&
 
 } // namespace cvflann
 
-#endif //TESTING_H
+#endif //_OPENCV_TESTING_H_
diff --git a/modules/flann/include/opencv2/flann/kdtree_index.h b/modules/flann/include/opencv2/flann/kdtree_index.h
index 58fc2ce71b..ca38750329 100644
--- a/modules/flann/include/opencv2/flann/kdtree_index.h
+++ b/modules/flann/include/opencv2/flann/kdtree_index.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef KDTREE_H
-#define KDTREE_H
+#ifndef _OPENCV_KDTREE_H_
+#define _OPENCV_KDTREE_H_
 
 #include <algorithm>
 #include <map>
@@ -619,4 +619,4 @@ private:
 
 } // namespace cvflann
 
-#endif //KDTREE_H
+#endif //_OPENCV_KDTREE_H_
diff --git a/modules/flann/include/opencv2/flann/kmeans_index.h b/modules/flann/include/opencv2/flann/kmeans_index.h
index 6ed4dac51e..e382f983df 100644
--- a/modules/flann/include/opencv2/flann/kmeans_index.h
+++ b/modules/flann/include/opencv2/flann/kmeans_index.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef KMEANSTREE_H
-#define KMEANSTREE_H
+#ifndef _OPENCV_KMEANSTREE_H_
+#define _OPENCV_KMEANSTREE_H_
 
 #include <algorithm>
 #include <string>
@@ -1114,4 +1114,4 @@ private:
 
 } // namespace cvflann
 
-#endif //KMEANSTREE_H
+#endif //_OPENCV_KMEANSTREE_H_
diff --git a/modules/flann/include/opencv2/flann/linear_index.h b/modules/flann/include/opencv2/flann/linear_index.h
index e55ef08408..f114965085 100644
--- a/modules/flann/include/opencv2/flann/linear_index.h
+++ b/modules/flann/include/opencv2/flann/linear_index.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef LINEARSEARCH_H
-#define LINEARSEARCH_H
+#ifndef _OPENCV_LINEARSEARCH_H_
+#define _OPENCV_LINEARSEARCH_H_
 
 #include "opencv2/flann/general.h"
 #include "opencv2/flann/nn_index.h"
@@ -117,4 +117,4 @@ public:
 
 } // namespace cvflann
 
-#endif // LINEARSEARCH_H
+#endif // _OPENCV_LINEARSEARCH_H_
diff --git a/modules/flann/include/opencv2/flann/logger.h b/modules/flann/include/opencv2/flann/logger.h
index d8a9edc521..7fac1de72a 100644
--- a/modules/flann/include/opencv2/flann/logger.h
+++ b/modules/flann/include/opencv2/flann/logger.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef LOGGER_H
-#define LOGGER_H
+#ifndef _OPENCV_LOGGER_H_
+#define _OPENCV_LOGGER_H_
 
 
 #include <cstdio>
@@ -88,4 +88,4 @@ CV_EXPORTS Logger& logger();
 
 } // namespace cvflann
 
-#endif //LOGGER_H
+#endif //_OPENCV_LOGGER_H_
diff --git a/modules/flann/include/opencv2/flann/matrix.h b/modules/flann/include/opencv2/flann/matrix.h
index a293892f0c..590df890a1 100644
--- a/modules/flann/include/opencv2/flann/matrix.h
+++ b/modules/flann/include/opencv2/flann/matrix.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef DATASET_H
-#define DATASET_H
+#ifndef _OPENCV_DATASET_H_
+#define _OPENCV_DATASET_H_
 
 #include <stdio.h>
 
@@ -115,4 +115,4 @@ public:
 
 } // namespace cvflann
 
-#endif //DATASET_H
+#endif //_OPENCV_DATASET_H_
diff --git a/modules/flann/include/opencv2/flann/nn_index.h b/modules/flann/include/opencv2/flann/nn_index.h
index 7113c9fde4..8db8980ad1 100644
--- a/modules/flann/include/opencv2/flann/nn_index.h
+++ b/modules/flann/include/opencv2/flann/nn_index.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef NNINDEX_H
-#define NNINDEX_H
+#ifndef _OPENCV_NNINDEX_H_
+#define _OPENCV_NNINDEX_H_
 
 #include <string>
 
@@ -105,4 +105,4 @@ public:
 
 } // namespace cvflann
 
-#endif //NNINDEX_H
+#endif //_OPENCV_NNINDEX_H_
diff --git a/modules/flann/include/opencv2/flann/object_factory.h b/modules/flann/include/opencv2/flann/object_factory.h
index dd3846d299..927c7c233c 100644
--- a/modules/flann/include/opencv2/flann/object_factory.h
+++ b/modules/flann/include/opencv2/flann/object_factory.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef OPENCV_OBJECT_FACTORY_H_
-#define OPENCV_OBJECT_FACTORY_H_
+#ifndef _OPENCV_OBJECT_FACTORY_H_
+#define _OPENCV_OBJECT_FACTORY_H_
 
 #include "opencv2/core/types_c.h"
 #include <map>
diff --git a/modules/flann/include/opencv2/flann/random.h b/modules/flann/include/opencv2/flann/random.h
index c491ea162c..71d94bdc0a 100644
--- a/modules/flann/include/opencv2/flann/random.h
+++ b/modules/flann/include/opencv2/flann/random.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef RANDOM_H
-#define RANDOM_H
+#ifndef _OPENCV_RANDOM_H_
+#define _OPENCV_RANDOM_H_
 
 #include <algorithm>
 #include <cstdlib>
@@ -131,4 +131,4 @@ public:
 
 } // namespace cvflann
 
-#endif //RANDOM_H
+#endif //_OPENCV_RANDOM_H_
diff --git a/modules/flann/include/opencv2/flann/result_set.h b/modules/flann/include/opencv2/flann/result_set.h
index b6a084d81c..c6b6de9e78 100644
--- a/modules/flann/include/opencv2/flann/result_set.h
+++ b/modules/flann/include/opencv2/flann/result_set.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef RESULTSET_H
-#define RESULTSET_H
+#ifndef _OPENCV_RESULTSET_H_
+#define _OPENCV_RESULTSET_H_
 
 
 #include <algorithm>
@@ -317,4 +317,4 @@ public:
 
 } // namespace cvflann
 
-#endif //RESULTSET_H
+#endif //_OPENCV_RESULTSET_H_
diff --git a/modules/flann/include/opencv2/flann/sampling.h b/modules/flann/include/opencv2/flann/sampling.h
index 22401829cb..bc661ff936 100644
--- a/modules/flann/include/opencv2/flann/sampling.h
+++ b/modules/flann/include/opencv2/flann/sampling.h
@@ -27,8 +27,8 @@
  *************************************************************************/
 
 
-#ifndef SAMPLING_H_
-#define SAMPLING_H_
+#ifndef _OPENCV_SAMPLING_H_
+#define _OPENCV_SAMPLING_H_
 
 
 #include "opencv2/flann/matrix.h"
@@ -91,4 +91,4 @@ Matrix<T> random_sample(const Matrix<T>& srcMatrix, size_t size)
 
 } // namespace cvflann
 
-#endif /* SAMPLING_H_ */
+#endif /* _OPENCV_SAMPLING_H_ */
diff --git a/modules/flann/include/opencv2/flann/saving.h b/modules/flann/include/opencv2/flann/saving.h
index d54db3515e..4fadf1e9b2 100644
--- a/modules/flann/include/opencv2/flann/saving.h
+++ b/modules/flann/include/opencv2/flann/saving.h
@@ -26,8 +26,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef SAVING_H_
-#define SAVING_H_
+#ifndef _OPENCV_SAVING_H_
+#define _OPENCV_SAVING_H_
 
 #include "opencv2/flann/general.h"
 #include "opencv2/flann/nn_index.h"
@@ -112,4 +112,4 @@ void load_value(FILE* stream, T& value, int count = 1)
 
 } // namespace cvflann
 
-#endif /* SAVING_H_ */
+#endif /* _OPENCV_SAVING_H_ */
diff --git a/modules/flann/include/opencv2/flann/simplex_downhill.h b/modules/flann/include/opencv2/flann/simplex_downhill.h
index 18c42ca759..21d3e944b1 100644
--- a/modules/flann/include/opencv2/flann/simplex_downhill.h
+++ b/modules/flann/include/opencv2/flann/simplex_downhill.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef SIMPLEX_DOWNHILL_H
-#define SIMPLEX_DOWNHILL_H
+#ifndef _OPENCV_SIMPLEX_DOWNHILL_H_
+#define _OPENCV_SIMPLEX_DOWNHILL_H_
 
 namespace cvflann
 {
@@ -183,4 +183,4 @@ float optimizeSimplexDownhill(T* points, int n, F func, float* vals = NULL )
 
 } // namespace cvflann
 
-#endif //SIMPLEX_DOWNHILL_H
+#endif //_OPENCV_SIMPLEX_DOWNHILL_H_
diff --git a/modules/flann/include/opencv2/flann/timer.h b/modules/flann/include/opencv2/flann/timer.h
index 09cd306a94..db320572b2 100644
--- a/modules/flann/include/opencv2/flann/timer.h
+++ b/modules/flann/include/opencv2/flann/timer.h
@@ -28,8 +28,8 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *************************************************************************/
 
-#ifndef TIMER_H
-#define TIMER_H
+#ifndef _OPENCV_TIMER_H_
+#define _OPENCV_TIMER_H_
 
 #include <time.h>
 
@@ -87,4 +87,4 @@ public:
 
 }// namespace cvflann
 
-#endif // TIMER_H
+#endif // _OPENCV_TIMER_H_