diff --git a/modules/highgui/src/window_QT.h b/modules/highgui/src/window_QT.h
index a06d9b750f..b132f41ede 100644
--- a/modules/highgui/src/window_QT.h
+++ b/modules/highgui/src/window_QT.h
@@ -278,9 +278,9 @@ public:
     QPointer<QBoxLayout> myLayout;
 
 private:
-    void closeEvent ( QCloseEvent * e );
-    void showEvent ( QShowEvent * event ) ;
-    void hideEvent ( QHideEvent * event ) ;
+    void closeEvent ( QCloseEvent * e ) CV_OVERRIDE;
+    void showEvent ( QShowEvent * event ) CV_OVERRIDE;
+    void hideEvent ( QHideEvent * event ) CV_OVERRIDE;
 };
 
 
@@ -339,7 +339,7 @@ public:
     QPointer<QLabel> myStatusBar_msg;
 
 protected:
-    virtual void keyPressEvent(QKeyEvent* event);
+    virtual void keyPressEvent(QKeyEvent* event) CV_OVERRIDE;
 
 private:
 
@@ -414,8 +414,8 @@ class OCVViewPort : public ViewPort
 {
 public:
     explicit OCVViewPort();
-    ~OCVViewPort() {};
-    void setMouseCallBack(CvMouseCallback callback, void* param);
+    ~OCVViewPort() CV_OVERRIDE {};
+    void setMouseCallBack(CvMouseCallback callback, void* param) CV_OVERRIDE;
 
 protected:
     void icvmouseEvent(QMouseEvent* event, type_mouse_event category);
@@ -433,38 +433,38 @@ class OpenGlViewPort : public QGLWidget, public OCVViewPort
 {
 public:
     explicit OpenGlViewPort(QWidget* parent);
-    ~OpenGlViewPort();
+    ~OpenGlViewPort() CV_OVERRIDE;
 
-    QWidget* getWidget();
+    QWidget* getWidget() CV_OVERRIDE;
 
-    void writeSettings(QSettings& settings);
-    void readSettings(QSettings& settings);
+    void writeSettings(QSettings& settings) CV_OVERRIDE;
+    void readSettings(QSettings& settings) CV_OVERRIDE;
 
-    double getRatio();
-    void setRatio(int flags);
+    double getRatio() CV_OVERRIDE;
+    void setRatio(int flags) CV_OVERRIDE;
 
-    void updateImage(const CvArr* arr);
+    void updateImage(const CvArr* arr) CV_OVERRIDE;
 
-    void startDisplayInfo(QString text, int delayms);
+    void startDisplayInfo(QString text, int delayms) CV_OVERRIDE;
 
-    void setOpenGlDrawCallback(CvOpenGlDrawCallback callback, void* userdata);
-    void makeCurrentOpenGlContext();
-    void updateGl();
+    void setOpenGlDrawCallback(CvOpenGlDrawCallback callback, void* userdata) CV_OVERRIDE;
+    void makeCurrentOpenGlContext() CV_OVERRIDE;
+    void updateGl() CV_OVERRIDE;
 
-    void setSize(QSize size_);
+    void setSize(QSize size_) CV_OVERRIDE;
 
 protected:
-    void initializeGL();
-    void resizeGL(int w, int h);
-    void paintGL();
+    void initializeGL() CV_OVERRIDE;
+    void resizeGL(int w, int h) CV_OVERRIDE;
+    void paintGL() CV_OVERRIDE;
 
-    void wheelEvent(QWheelEvent* event);
-    void mouseMoveEvent(QMouseEvent* event);
-    void mousePressEvent(QMouseEvent* event);
-    void mouseReleaseEvent(QMouseEvent* event);
-    void mouseDoubleClickEvent(QMouseEvent* event);
+    void wheelEvent(QWheelEvent* event) CV_OVERRIDE;
+    void mouseMoveEvent(QMouseEvent* event) CV_OVERRIDE;
+    void mousePressEvent(QMouseEvent* event) CV_OVERRIDE;
+    void mouseReleaseEvent(QMouseEvent* event) CV_OVERRIDE;
+    void mouseDoubleClickEvent(QMouseEvent* event) CV_OVERRIDE;
 
-    QSize sizeHint() const;
+    QSize sizeHint() const CV_OVERRIDE;
 
 private:
     QSize size;
@@ -482,25 +482,25 @@ class DefaultViewPort : public QGraphicsView, public OCVViewPort
 
 public:
     DefaultViewPort(CvWindow* centralWidget, int arg2);
-    ~DefaultViewPort();
+    ~DefaultViewPort() CV_OVERRIDE;
 
-    QWidget* getWidget();
+    QWidget* getWidget() CV_OVERRIDE;
 
-    void writeSettings(QSettings& settings);
-    void readSettings(QSettings& settings);
+    void writeSettings(QSettings& settings) CV_OVERRIDE;
+    void readSettings(QSettings& settings) CV_OVERRIDE;
 
-    double getRatio();
-    void setRatio(int flags);
+    double getRatio() CV_OVERRIDE;
+    void setRatio(int flags) CV_OVERRIDE;
 
-    void updateImage(const CvArr* arr);
+    void updateImage(const CvArr* arr) CV_OVERRIDE;
 
-    void startDisplayInfo(QString text, int delayms);
+    void startDisplayInfo(QString text, int delayms) CV_OVERRIDE;
 
-    void setOpenGlDrawCallback(CvOpenGlDrawCallback callback, void* userdata);
-    void makeCurrentOpenGlContext();
-    void updateGl();
+    void setOpenGlDrawCallback(CvOpenGlDrawCallback callback, void* userdata) CV_OVERRIDE;
+    void makeCurrentOpenGlContext() CV_OVERRIDE;
+    void updateGl() CV_OVERRIDE;
 
-    void setSize(QSize size_);
+    void setSize(QSize size_) CV_OVERRIDE;
 
 public slots:
     //reference:
@@ -520,15 +520,15 @@ public slots:
     void saveView();
 
 protected:
-    void contextMenuEvent(QContextMenuEvent* event);
-    void resizeEvent(QResizeEvent* event);
-    void paintEvent(QPaintEvent* paintEventInfo);
+    void contextMenuEvent(QContextMenuEvent* event) CV_OVERRIDE;
+    void resizeEvent(QResizeEvent* event) CV_OVERRIDE;
+    void paintEvent(QPaintEvent* paintEventInfo) CV_OVERRIDE;
 
-    void wheelEvent(QWheelEvent* event);
-    void mouseMoveEvent(QMouseEvent* event);
-    void mousePressEvent(QMouseEvent* event);
-    void mouseReleaseEvent(QMouseEvent* event);
-    void mouseDoubleClickEvent(QMouseEvent* event);
+    void wheelEvent(QWheelEvent* event) CV_OVERRIDE;
+    void mouseMoveEvent(QMouseEvent* event) CV_OVERRIDE;
+    void mousePressEvent(QMouseEvent* event) CV_OVERRIDE;
+    void mouseReleaseEvent(QMouseEvent* event) CV_OVERRIDE;
+    void mouseDoubleClickEvent(QMouseEvent* event) CV_OVERRIDE;
 
 private:
     int param_keepRatio;
@@ -552,7 +552,7 @@ private:
 
     bool isSameSize(IplImage* img1,IplImage* img2);
 
-    QSize sizeHint() const;
+    QSize sizeHint() const CV_OVERRIDE;
     QPointer<CvWindow> centralWidget;
     QPointer<QTimer> timerDisplay;
     bool drawInfo;
@@ -566,7 +566,7 @@ private:
     void drawStatusBar();
     void controlImagePosition();
 
-    void icvmouseProcessing(QPointF pt, int cv_event, int flags);
+    void icvmouseProcessing(QPointF pt, int cv_event, int flags) CV_OVERRIDE;
 
 private slots:
     void stopDisplayInfo();
diff --git a/samples/opengl/opengl_interop.cpp b/samples/opengl/opengl_interop.cpp
index 5690ee1e8b..1d606f13fe 100644
--- a/samples/opengl/opengl_interop.cpp
+++ b/samples/opengl/opengl_interop.cpp
@@ -32,6 +32,8 @@
 # pragma comment(lib, "glu32.lib")
 #endif
 
+using namespace cv;
+
 /*
 // Press key   to
 //       1     processing on CPU
@@ -64,7 +66,7 @@ public:
 
     ~GLWinApp() {}
 
-    virtual void cleanup()
+    virtual void cleanup() CV_OVERRIDE
     {
         m_shutdown = true;
 #if defined(__linux__)
@@ -75,7 +77,7 @@ public:
     }
 
 #if defined(_WIN32)
-    virtual LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
+    virtual LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) CV_OVERRIDE
     {
         switch (message)
         {
@@ -121,7 +123,7 @@ public:
 #endif
 
 #if defined(__linux__)
-    int handle_event(XEvent& e)
+    int handle_event(XEvent& e) CV_OVERRIDE
     {
         switch(e.type)
         {
@@ -167,7 +169,7 @@ public:
     }
 #endif
 
-    int init()
+    int init() CV_OVERRIDE
     {
 #if defined(_WIN32)
         m_hDC = GetDC(m_hWnd);
@@ -258,12 +260,12 @@ public:
 #endif
     }
 
-    void idle()
+    void idle() CV_OVERRIDE
     {
         render();
     }
 
-    int render()
+    int render() CV_OVERRIDE
     {
         try
         {