diff --git a/core/sample-vpColor.cpp b/core/sample-vpColor.cpp
index c46c637..a17c615 100644
--- a/core/sample-vpColor.cpp
+++ b/core/sample-vpColor.cpp
@@ -20,7 +20,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #endif
 
diff --git a/core/sample-vpImageConvert-3.cpp b/core/sample-vpImageConvert-3.cpp
deleted file mode 100644
index 73549f3..0000000
--- a/core/sample-vpImageConvert-3.cpp
+++ /dev/null
@@ -1,25 +0,0 @@
-#include <visp3/core/vpImage.h>
-#include <visp3/core/vpImageConvert.h>
-#include <visp3/io/vpImageIo.h>
-
-int main()
-{
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION < 0x020408)
-  vpImage<vpRGBa> Ic; // A color image
-  IplImage* Ip = NULL;
-
-  // Read an image on a disk
-  vpImageIo::readPPM(Ic, "image.ppm");
-  // Convert the vpImage<vpRGBa> in to color IplImage
-  vpImageConvert::convert(Ic, Ip);
-  // Treatments on IplImage
-  //...
-  // Save the IplImage on the disk
-  cvSaveImage("Ipl.ppm", Ip);
-
-  //Release Ip header and data
-  cvReleaseImage(&Ip);
-#endif
-}
-
-
diff --git a/core/sample-vpImageConvert-4.cpp b/core/sample-vpImageConvert-4.cpp
deleted file mode 100644
index f16d5d7..0000000
--- a/core/sample-vpImageConvert-4.cpp
+++ /dev/null
@@ -1,24 +0,0 @@
-#include <visp3/core/vpImage.h>
-#include <visp3/core/vpImageConvert.h>
-#include <visp3/io/vpImageIo.h>
-
-int main()
-{
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION < 0x020408)
-  vpImage<unsigned char> Ig; // A greyscale image
-  IplImage* Ip = NULL;
-
-  // Read an image on a disk
-  vpImageIo::readPGM(Ig, "image.pgm");
-  // Convert the vpImage<unsigned char> in to greyscale IplImage
-  vpImageConvert::convert(Ig, Ip);
-  // Treatments on IplImage Ip
-  //...
-  // Save the IplImage on the disk
-  cvSaveImage("Ipl.pgm", Ip);
-
-  //Release Ip header and data
-  cvReleaseImage(&Ip);
-#endif
-}
-
diff --git a/core/sample-vpImageConvert-6.cpp b/core/sample-vpImageConvert-6.cpp
index ae1de1e..9212180 100644
--- a/core/sample-vpImageConvert-6.cpp
+++ b/core/sample-vpImageConvert-6.cpp
@@ -8,13 +8,13 @@
 
 int main()
 {
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100) && defined(HAVE_OPENCV_IMGCODECS)
-  vpImage<unsigned char> Ig; // A greyscale image
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_IMGCODECS)
+  vpImage<unsigned char> Ig; // A grayscale image
   cv::Mat Ip;
 
   // Read an image on a disk
   vpImageIo::readPGM(Ig, "image.pgm");
-  // Convert the vpImage<unsigned char> in to greyscale cv::Mat
+  // Convert the vpImage<unsigned char> in to grayscale cv::Mat
   vpImageConvert::convert(Ig, Ip);
   // Treatments on cv::Mat Ip
   //...
diff --git a/core/sample-vpImageConvert-7.cpp b/core/sample-vpImageConvert-7.cpp
deleted file mode 100644
index cf045ff..0000000
--- a/core/sample-vpImageConvert-7.cpp
+++ /dev/null
@@ -1,26 +0,0 @@
-#include <visp3/core/vpImage.h>
-#include <visp3/core/vpImageConvert.h>
-#include <visp3/io/vpImageIo.h>
-
-#if defined(HAVE_OPENCV_IMGCODECS)
-#include <opencv2/imgcodecs.hpp>
-#endif
-
-int main()
-{
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100) && defined(HAVE_OPENCV_IMGCODECS)
-  vpImage<unsigned char> Ig; // A greyscale image
-  cv::Mat Ip;
-
-  // Read an image on a disk
-  vpImageIo::readPGM(Ig, "image.pgm");
-  // Convert the vpImage<unsigned char> in to color cv::Mat.
-  vpImageConvert::convert(Ig, Ip);
-  // Treatments on cv::Mat Ip
-  //...
-  // Save the cv::Mat on the disk
-  cv::imwrite("image.pgm", Ip);
-#endif
-}
-
-
diff --git a/core/sample-vpImageConvert-8.cpp b/core/sample-vpImageConvert-8.cpp
index c277c18..9159fd1 100644
--- a/core/sample-vpImageConvert-8.cpp
+++ b/core/sample-vpImageConvert-8.cpp
@@ -8,7 +8,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100) && defined(HAVE_OPENCV_IMGCODECS)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_IMGCODECS)
   vpImage<unsigned char> Ig; // A grayscale image
   cv::Mat Ip;
 
diff --git a/core/sample-vpImageConvert-9.cpp b/core/sample-vpImageConvert-9.cpp
index 6765473..195e584 100644
--- a/core/sample-vpImageConvert-9.cpp
+++ b/core/sample-vpImageConvert-9.cpp
@@ -9,7 +9,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100) && defined(HAVE_OPENCV_IMGCODECS)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_IMGCODECS)
   vpImage<vpRGBa> Ic; // A color image
   cv::Mat Ip;
 
diff --git a/core/sample-vpImageConvert.cpp b/core/sample-vpImageConvert.cpp
deleted file mode 100644
index 6f6649e..0000000
--- a/core/sample-vpImageConvert.cpp
+++ /dev/null
@@ -1,21 +0,0 @@
-#include <visp3/core/vpImage.h>
-#include <visp3/core/vpImageConvert.h>
-#include <visp3/io/vpImageIo.h>
-
-int main()
-{
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION < 0x020408)
-  vpImage<unsigned char> Ig; // A grayscale image
-  IplImage* Ip;
-
-  // Read an image on a disk with openCV library
-  Ip = cvLoadImage("image.pgm", CV_LOAD_IMAGE_GRAYSCALE);
-  // Convert the grayscale IplImage into vpImage<unsigned char>
-  vpImageConvert::convert(Ip, Ig);
-
-  // ...
-
-  // Release Ip header and data
-  cvReleaseImage(&Ip);
-#endif
-}
diff --git a/core/sample-vpImageFilter.cpp b/core/sample-vpImageFilter.cpp
index cbb8cb4..80128cd 100644
--- a/core/sample-vpImageFilter.cpp
+++ b/core/sample-vpImageFilter.cpp
@@ -3,7 +3,7 @@
 
 int main()
 {
-#if (VISP_HAVE_OPENCV_VERSION >= 0x020100) && (VISP_HAVE_OPENCV_VERSION < 0x030000) // Cany uses OpenCV >=2.1.0 and < 3.0.0
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC)
   // Constants for the Canny operator.
   const unsigned int gaussianFilterSize = 5;
   const double thresholdCanny = 15;
@@ -13,9 +13,9 @@ int main()
   vpImage<unsigned char> Isrc;
   vpImage<unsigned char> Icanny;
 
-  //First grab the source image Isrc.
+  // First grab the source image Isrc.
 
-  //Apply the Canny edge operator and set the Icanny image.
+  // Apply the Canny edge operator and set the Icanny image.
   vpImageFilter::canny(Isrc, Icanny, gaussianFilterSize, thresholdCanny, apertureSobel);
 #endif
   return (0);
diff --git a/detection/sample-vpDetectorFace.cpp b/detection/sample-vpDetectorFace.cpp
index 1288f0b..c1d0b50 100644
--- a/detection/sample-vpDetectorFace.cpp
+++ b/detection/sample-vpDetectorFace.cpp
@@ -2,13 +2,13 @@
 
 int main()
 {
-#if (VISP_HAVE_OPENCV_VERSION >= 0x020200)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_OBJDETECT)
   vpImage<unsigned char> I;
   vpDetectorFace face_detector;
   face_detector.setCascadeClassifierFile("haarcascade_frontalface_alt.xml");
 
-  while(1) {
-    // acquire a new image in I
+  while (1) {
+    // Acquire a new image in I
     bool face_found = face_detector.detect(I);
     if (face_found) {
       vpRect face_bbox = face_detector.getBBox(0); // largest face has index 0
diff --git a/gui/sample-vpDisplay-2.cpp b/gui/sample-vpDisplay-2.cpp
index 83d4b2f..b9fad35 100644
--- a/gui/sample-vpDisplay-2.cpp
+++ b/gui/sample-vpDisplay-2.cpp
@@ -23,7 +23,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #endif
 
@@ -43,11 +43,11 @@ int main()
   vpDisplay::flush(I);
 
   // Updates the color image with the original loaded image and the overlay
-  vpDisplay::getImage(I, Ioverlay) ;
+  vpDisplay::getImage(I, Ioverlay);
 
   // Write the color image on the disk
   std::string ofilename("overlay.ppm");
-  vpImageIo::writePPM(Ioverlay, ofilename) ;
+  vpImageIo::writePPM(Ioverlay, ofilename);
 
   // Wait for a click in the display window
   vpDisplay::getClick(I);
diff --git a/gui/sample-vpDisplay-3.cpp b/gui/sample-vpDisplay-3.cpp
index 26e4d21..bc037f7 100644
--- a/gui/sample-vpDisplay-3.cpp
+++ b/gui/sample-vpDisplay-3.cpp
@@ -23,7 +23,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #endif
 
@@ -42,11 +42,11 @@ int main()
   vpDisplay::flush(I);
 
   // Updates the color image with the original loaded image and the overlay
-  vpDisplay::getImage(I, Ioverlay) ;
+  vpDisplay::getImage(I, Ioverlay);
 
   // Write the color image on the disk
   std::string ofilename("overlay.ppm");
-  vpImageIo::writePPM(Ioverlay, ofilename) ;
+  vpImageIo::writePPM(Ioverlay, ofilename);
 
   // Wait for a click in the display window
   vpDisplay::getClick(I);
diff --git a/gui/sample-vpDisplay-4.cpp b/gui/sample-vpDisplay-4.cpp
index 1e53c9b..3589f5b 100644
--- a/gui/sample-vpDisplay-4.cpp
+++ b/gui/sample-vpDisplay-4.cpp
@@ -20,7 +20,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #else
   std::cout << "Sorry, no video device is available" << std::endl;
@@ -52,11 +52,11 @@ int main()
     event = vpDisplay::getKeyboardEvent(I, &key[0], false);
     if (event) {
       std::cout << "Key detected: " << key << std::endl;
-      cpt_event ++;
+      cpt_event++;
     }
 
     vpTime::wait(5); // wait 5 ms
-  } while(cpt_event < 5);
+  } while (cpt_event < 5);
 
 #ifdef VISP_HAVE_DISPLAY
   delete d;
diff --git a/gui/sample-vpDisplay-5.cpp b/gui/sample-vpDisplay-5.cpp
index 3bda7e4..40ee794 100644
--- a/gui/sample-vpDisplay-5.cpp
+++ b/gui/sample-vpDisplay-5.cpp
@@ -18,7 +18,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #else
   std::cout << "Sorry, no video device is available" << std::endl;
@@ -50,11 +50,11 @@ int main()
     event = vpDisplay::getKeyboardEvent(I, &key[0], false);
     if (event) {
       std::cout << "Key detected: " << key << std::endl;
-      cpt_event ++;
+      cpt_event++;
     }
 
     vpTime::wait(5); // wait 5 ms
-  } while(cpt_event < 5);
+  } while (cpt_event < 5);
 
 #ifdef VISP_HAVE_DISPLAY
   delete d;
diff --git a/gui/sample-vpDisplay-6.cpp b/gui/sample-vpDisplay-6.cpp
index 3bda7e4..40ee794 100644
--- a/gui/sample-vpDisplay-6.cpp
+++ b/gui/sample-vpDisplay-6.cpp
@@ -18,7 +18,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #else
   std::cout << "Sorry, no video device is available" << std::endl;
@@ -50,11 +50,11 @@ int main()
     event = vpDisplay::getKeyboardEvent(I, &key[0], false);
     if (event) {
       std::cout << "Key detected: " << key << std::endl;
-      cpt_event ++;
+      cpt_event++;
     }
 
     vpTime::wait(5); // wait 5 ms
-  } while(cpt_event < 5);
+  } while (cpt_event < 5);
 
 #ifdef VISP_HAVE_DISPLAY
   delete d;
diff --git a/gui/sample-vpDisplay-7.cpp b/gui/sample-vpDisplay-7.cpp
index caef39f..b71cfdc 100644
--- a/gui/sample-vpDisplay-7.cpp
+++ b/gui/sample-vpDisplay-7.cpp
@@ -21,7 +21,7 @@ int main()
   d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
   d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
+#elif defined(HAVE_OPENCV_HIGHGUI)
   d = new vpDisplayOpenCV;
 #else
   std::cout << "Sorry, no video device is available" << std::endl;
diff --git a/gui/sample-vpDisplay.cpp b/gui/sample-vpDisplay.cpp
index 83c9859..6077921 100644
--- a/gui/sample-vpDisplay.cpp
+++ b/gui/sample-vpDisplay.cpp
@@ -7,88 +7,88 @@
 
 int main()
 {
-  try {
-    vpImage<unsigned char> I; // Grey level image
+    try {
+        vpImage<unsigned char> I; // Grey level image
 
-    // Read an image in PGM P5 format
+        // Read an image in PGM P5 format
 #ifdef _WIN32
-    std::string filename("C:/temp/ViSP-images/Klimt/Klimt.ppm");
+        std::string filename("C:/temp/ViSP-images/Klimt/Klimt.ppm");
 #else
-    std::string filename("/local/soft/ViSP/ViSP-images/Klimt/Klimt.ppm");
+        std::string filename("/local/soft/ViSP/ViSP-images/Klimt/Klimt.ppm");
 #endif
 
-    vpDisplay *d;
+        vpDisplay *d;
 
-    // Depending on the detected third party libraries, we instantiate here the
-    // first video device which is available
+        // Depending on the detected third party libraries, we instantiate here the
+        // first video device which is available
 #if defined(VISP_HAVE_X11)
-    d = new vpDisplayX;
+        d = new vpDisplayX;
 #elif defined(VISP_HAVE_GTK)
-    d = new vpDisplayGTK;
+        d = new vpDisplayGTK;
 #elif defined(VISP_HAVE_GDI)
-    d = new vpDisplayGDI;
+        d = new vpDisplayGDI;
 #elif defined(VISP_HAVE_D3D9)
-    d = new vpDisplayD3D;
-#elif defined(VISP_HAVE_OPENCV)
-    d = new vpDisplayOpenCV;
+        d = new vpDisplayD3D;
+#elif defined(HAVE_OPENCV_HIGHGUI)
+        d = new vpDisplayOpenCV;
 #endif
 
-    // Initialize the display with the image I. Display and image are
-    // now link together.
+        // Initialize the display with the image I. Display and image are
+        // now link together.
 #ifdef VISP_HAVE_DISPLAY
-    d->init(I);
+        d->init(I);
 #endif
 
-    // Specify the window location
-    vpDisplay::setWindowPosition(I, 400, 100);
-
-    // Set the display window title
-    vpDisplay::setTitle(I, "My image");
-
-    // To initialize the video device, it is also possible to replace
-    // the 3 previous lines by:
-    // d->init(I, 400, 100, "My image");
-
-    // Set the display background with image I content
-    vpDisplay::display(I);
-
-    // Draw a red rectangle in the display overlay (foreground)
-    vpDisplay::displayRectangle(I, 10, 10, 100, 20, vpColor::red, true);
-
-    // Draw a red rectangle in the display overlay (foreground)
-    vpImagePoint topLeftCorner;
-    topLeftCorner.set_i(50);
-    topLeftCorner.set_j(10);
-    vpDisplay::displayRectangle(I, topLeftCorner, 100, 20, vpColor::green, true);
-
-    // Flush the foreground and background display
-    vpDisplay::flush(I);
-
-    // Get non blocking keyboard events
-    std::cout << "Check keyboard events..." << std::endl;
-    char key[10];
-    bool ret;
-    for (int i=0; i< 200; i++) {
-      bool ret = vpDisplay::getKeyboardEvent(I, key, false);
-      if (ret)
-        std::cout << "keyboard event: key: " << "\"" << key << "\"" << std::endl;
-      vpTime::wait(40);
-    }
-
-    // Get a blocking keyboard event
-    std::cout << "Wait for a keyboard event..." << std::endl;
-    ret = vpDisplay::getKeyboardEvent(I, key, true);
-    std::cout << "keyboard event: " << ret << std::endl;
-    if (ret)
-      std::cout << "key: " << "\"" << key << "\"" << std::endl;
-
-    // Wait for a click in the display window
-    std::cout << "Wait for a button click..." << std::endl;
-    vpDisplay::getClick(I);
+        // Specify the window location
+        vpDisplay::setWindowPosition(I, 400, 100);
+
+        // Set the display window title
+        vpDisplay::setTitle(I, "My image");
+
+        // To initialize the video device, it is also possible to replace
+        // the 3 previous lines by:
+        // d->init(I, 400, 100, "My image");
+
+        // Set the display background with image I content
+        vpDisplay::display(I);
+
+        // Draw a red rectangle in the display overlay (foreground)
+        vpDisplay::displayRectangle(I, 10, 10, 100, 20, vpColor::red, true);
+
+        // Draw a red rectangle in the display overlay (foreground)
+        vpImagePoint topLeftCorner;
+        topLeftCorner.set_i(50);
+        topLeftCorner.set_j(10);
+        vpDisplay::displayRectangle(I, topLeftCorner, 100, 20, vpColor::green, true);
+
+        // Flush the foreground and background display
+        vpDisplay::flush(I);
+
+        // Get non blocking keyboard events
+        std::cout << "Check keyboard events..." << std::endl;
+        char key[10];
+        bool ret;
+        for (int i = 0; i < 200; i++) {
+            bool ret = vpDisplay::getKeyboardEvent(I, key, false);
+            if (ret)
+                std::cout << "keyboard event: key: " << "\"" << key << "\"" << std::endl;
+            vpTime::wait(40);
+        }
+
+        // Get a blocking keyboard event
+        std::cout << "Wait for a keyboard event..." << std::endl;
+        ret = vpDisplay::getKeyboardEvent(I, key, true);
+        std::cout << "keyboard event: " << ret << std::endl;
+        if (ret)
+            std::cout << "key: " << "\"" << key << "\"" << std::endl;
+
+        // Wait for a click in the display window
+        std::cout << "Wait for a button click..." << std::endl;
+        vpDisplay::getClick(I);
 
 #ifdef VISP_HAVE_DISPLAY
-    delete d;
+        delete d;
 #endif
-  }
-  catch(...) {}
+    }
+    catch (...) { }
 }
diff --git a/gui/sample-vpDisplayOpenCV.cpp b/gui/sample-vpDisplayOpenCV.cpp
index fb4afb7..45bb94b 100644
--- a/gui/sample-vpDisplayOpenCV.cpp
+++ b/gui/sample-vpDisplayOpenCV.cpp
@@ -3,11 +3,10 @@
 
 int main()
 {
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION < 0x030000)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_HIGHGUI)
   vpImage<unsigned char> I; // Grey level image
 
   // Read an image in PGM P5 format
-  //vpImageIo::readPGM(I, "/local/soft/ViSP/ViSP-images/Klimt/Klimt.pgm");
   vpImageIo::readPGM(I, "/tmp/Klimt.pgm");
 
   vpDisplayOpenCV d;
@@ -41,7 +40,7 @@ int main()
   std::cout << "Check keyboard events..." << std::endl;
   char key[10];
   bool ret;
-  for (int i=0; i< 200; i++) {
+  for (int i = 0; i < 200; i++) {
     bool ret = vpDisplay::getKeyboardEvent(I, key, false);
     if (ret)
       std::cout << "keyboard event: key: " << "\"" << key << "\"" << std::endl;
diff --git a/io/sample-vpVideoWriter.cpp b/io/sample-vpVideoWriter.cpp
index f1e477e..213a0dd 100644
--- a/io/sample-vpVideoWriter.cpp
+++ b/io/sample-vpVideoWriter.cpp
@@ -2,6 +2,7 @@
 
 int main()
 {
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_VIDEOIO) && defined(HAVE_OPENCV_HIGHGUI)
   vpImage<vpRGBa> I;
 
   vpVideoWriter writer;
@@ -10,17 +11,16 @@ int main()
   writer.setFramerate(30);
 
 #if VISP_HAVE_OPENCV_VERSION >= 0x030000
-  writer.setCodec( cv::VideoWriter::fourcc('P','I','M','1') );
-#elif VISP_HAVE_OPENCV_VERSION >= 0x020100
-  writer.setCodec( CV_FOURCC('P','I','M','1') );
+  writer.setCodec(cv::VideoWriter::fourcc('P', 'I', 'M', '1'));
+#else
+  writer.setCodec(CV_FOURCC('P', 'I', 'M', '1'));
 #endif
 
   writer.setFileName("./test.mpeg");
 
   writer.open(I);
 
-  for ( ; ; )
-  {
+  for (; ; ) {
     // Here the code to capture or create an image and store it in I.
 
     // Save the image
@@ -28,6 +28,6 @@ int main()
   }
 
   writer.close();
-
+#endif
   return 0;
 }
diff --git a/json/sample-json-vpMe.cpp b/json/sample-json-vpMe.cpp
index 66d1764..3a50ea6 100644
--- a/json/sample-json-vpMe.cpp
+++ b/json/sample-json-vpMe.cpp
@@ -6,7 +6,8 @@ int main()
   std::string filename = "me.json";
   {
     vpMe me;
-    me.setThreshold(10000);
+    me.setLikelihoodThresholdType(vpMe::NORMALIZED_THRESHOLD);
+    me.setThreshold(20);
     me.setMaskNumber(180);
     me.setMaskSign(0);
     me.setMu1(0.5);
diff --git a/klt/sample-vpKltOpencv.cpp b/klt/sample-vpKltOpencv.cpp
index 186d911..9952bfd 100644
--- a/klt/sample-vpKltOpencv.cpp
+++ b/klt/sample-vpKltOpencv.cpp
@@ -5,21 +5,20 @@
 
 int main()
 {
-#if (VISP_HAVE_OPENCV_VERSION >= 0x010100) && (VISP_HAVE_OPENCV_VERSION < 0x020408)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_HIGHGUI) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpImage<unsigned char> I;
-  IplImage* Icv = NULL;
+  cv::Mat Icv;
   vpKltOpencv klt;
 
-  //First grab the initial image I
+  // First grab the initial image I
 
-  //Convert the image I to the IplImage format.
+  // Convert the image I to the IplImage format.
   vpImageConvert::convert(I, Icv);
 
-  //Initialise the tracking on the whole image.
-  klt.initTracking(Icv, NULL);
+  // Initialise the tracking on the whole image.
+  klt.initTracking(Icv);
 
-  while(true)
-  {
+  while (true) {
     // Grab a new image and convert it to the OpenCV format.
     vpImageConvert::convert(I, Icv);
 
@@ -29,8 +28,6 @@ int main()
     // Display the features tracked at the current iteration.
     klt.display(I);
   }
-
-  cvReleaseImage(&Icv);
 #else
   std::cout << "vpKltOpencv requires ViSP with OpenCV." << std::endl;
 #endif
diff --git a/mbt/sample-vpMbEdgeKltTracker-1.cpp b/mbt/sample-vpMbEdgeKltTracker-1.cpp
index e3032c3..ad1f75b 100644
--- a/mbt/sample-vpMbEdgeKltTracker-1.cpp
+++ b/mbt/sample-vpMbEdgeKltTracker-1.cpp
@@ -7,7 +7,7 @@
 
 int main()
 {
-#if defined VISP_HAVE_OPENCV
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpMbEdgeKltTracker tracker; // Create an hybrid model based tracker.
   vpImage<unsigned char> I;
   vpHomogeneousMatrix cMo; // Pose used to display the model.
@@ -18,7 +18,7 @@ int main()
 
 #if defined VISP_HAVE_X11
   vpDisplayX display;
-  display.init(I,100,100,"Mb Hybrid Tracker");
+  display.init(I, 100, 100, "Mb Hybrid Tracker");
 #endif
 
   tracker.loadConfigFile("cube.xml"); // Load the configuration of the tracker
@@ -26,14 +26,13 @@ int main()
   // load the 3d model, to read .wrl model coin is required, if coin is not installed .cao file can be used.
   tracker.loadModel("cube.cao");
 
-  while(true){
+  while (true) {
     // acquire a new image
     // Get the pose using any method
     vpDisplay::display(I);
     tracker.display(I, cMo, cam, vpColor::darkRed, 1, true); // Display the model at the computed pose.
     vpDisplay::flush(I);
   }
-
 #endif
 
   return 0;
diff --git a/mbt/sample-vpMbEdgeKltTracker-2.cpp b/mbt/sample-vpMbEdgeKltTracker-2.cpp
index 72afdac..6d51981 100644
--- a/mbt/sample-vpMbEdgeKltTracker-2.cpp
+++ b/mbt/sample-vpMbEdgeKltTracker-2.cpp
@@ -7,7 +7,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION < 0x030000)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpMbEdgeKltTracker tracker; // Create an hybrid model based tracker.
   vpImage<unsigned char> I;
   vpHomogeneousMatrix cMo; // Pose used to display the model.
@@ -18,14 +18,14 @@ int main()
 
 #if defined VISP_HAVE_X11
   vpDisplayX display;
-  display.init(I,100,100,"Mb Hybrid Tracker");
+  display.init(I, 100, 100, "Mb Hybrid Tracker");
 #endif
 
   tracker.loadConfigFile("cube.xml"); // Load the configuration of the tracker
   tracker.getCameraParameters(cam); // Get the camera parameters used by the tracker (from the configuration file).
   tracker.loadModel("cube.cao"); // load the 3d model, to read .wrl model coi is required, if coin is not installed .cao file can be used.
 
-  while(true){
+  while (true) {
     // acquire a new image
     // Get the pose using any method
     vpDisplay::display(I);
diff --git a/mbt/sample-vpMbEdgeKltTracker.cpp b/mbt/sample-vpMbEdgeKltTracker.cpp
index b3d7622..f9009d6 100644
--- a/mbt/sample-vpMbEdgeKltTracker.cpp
+++ b/mbt/sample-vpMbEdgeKltTracker.cpp
@@ -8,7 +8,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_MODULE_KLT) && (defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100))
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpMbEdgeKltTracker tracker; // Create an hybrid model based tracker.
   vpImage<unsigned char> I;
   vpHomogeneousMatrix cMo; // Pose computed using the tracker.
@@ -19,15 +19,15 @@ int main()
 
 #if defined VISP_HAVE_X11
   vpDisplayX display;
-  display.init(I,100,100,"Mb Hybrid Tracker");
+  display.init(I, 100, 100, "Mb Hybrid Tracker");
 #endif
 
   tracker.loadConfigFile("cube.xml"); // Load the configuration of the tracker
   tracker.getCameraParameters(cam);   // Get the camera parameters used by the tracker (from the configuration file).
   tracker.loadModel("cube.cao");      // Load the 3d model in cao format. No 3rd party library is required
-  tracker.initClick(I, "cube.init");  // Initialise manually the pose by clicking on the image points associated to the 3d points containned in the cube.init file.
+  tracker.initClick(I, "cube.init");  // Initialise manually the pose by clicking on the image points associated to the 3d points contained in the cube.init file.
 
-  while(true){
+  while (true) {
     // Acquire a new image
     vpDisplay::display(I);
     tracker.track(I);     // Track the object on this image
diff --git a/mbt/sample-vpMbKltTracker-1.cpp b/mbt/sample-vpMbKltTracker-1.cpp
index 954ba0d..1c9abbd 100644
--- a/mbt/sample-vpMbKltTracker-1.cpp
+++ b/mbt/sample-vpMbKltTracker-1.cpp
@@ -6,7 +6,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_MODULE_KLT) && (defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100))
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpMbKltTracker tracker; // Create a model based tracker via Klt Points.
   vpImage<unsigned char> I;
   vpHomogeneousMatrix cMo; // Pose used in entry (has to be defined), then computed using the tracker.
@@ -18,7 +18,7 @@ int main()
   tracker.loadModel("cube.cao"); // load the 3d model, to read .wrl model coi is required, if coin is not installed .cao file can be used.
   tracker.initFromPose(I, cMo); // initialise the tracker with the given pose.
 
-  while(true){
+  while (true) {
     // acquire a new image
     tracker.track(I); // track the object on this image
     tracker.getPose(cMo); // get the pose
diff --git a/mbt/sample-vpMbKltTracker-2.cpp b/mbt/sample-vpMbKltTracker-2.cpp
index 207d304..95a3549 100644
--- a/mbt/sample-vpMbKltTracker-2.cpp
+++ b/mbt/sample-vpMbKltTracker-2.cpp
@@ -7,7 +7,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_MODULE_KLT) && (defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100))
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpMbKltTracker tracker; // Create a model based tracker via Klt Points.
   vpImage<unsigned char> I;
   vpHomogeneousMatrix cMo; // Pose used to display the model.
@@ -18,14 +18,14 @@ int main()
 
 #if defined VISP_HAVE_X11
   vpDisplayX display;
-  display.init(I,100,100,"Mb Klt Tracker");
+  display.init(I, 100, 100, "Mb Klt Tracker");
 #endif
 
   tracker.loadConfigFile("cube.xml"); // Load the configuration of the tracker
   tracker.getCameraParameters(cam); // Get the camera parameters used by the tracker (from the configuration file).
   tracker.loadModel("cube.cao"); // load the 3d model, to read .wrl model coi is required, if coin is not installed .cao file can be used.
 
-  while(true){
+  while (true) {
     // acquire a new image
     // Get the pose using any method
     vpDisplay::display(I);
diff --git a/mbt/sample-vpMbKltTracker.cpp b/mbt/sample-vpMbKltTracker.cpp
index 20305df..6c5da03 100644
--- a/mbt/sample-vpMbKltTracker.cpp
+++ b/mbt/sample-vpMbKltTracker.cpp
@@ -8,7 +8,7 @@
 
 int main()
 {
-#if defined(VISP_HAVE_MODULE_KLT) && (defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100))
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_VIDEO)
   vpMbKltTracker tracker; // Create a model based tracker via KLT points.
   vpImage<unsigned char> I;
   vpHomogeneousMatrix cMo; // Pose computed using the tracker.
@@ -19,15 +19,15 @@ int main()
 
 #if defined VISP_HAVE_X11
   vpDisplayX display;
-  display.init(I,100,100,"Mb Klt Tracker");
+  display.init(I, 100, 100, "Mb Klt Tracker");
 #endif
 
   tracker.loadConfigFile("cube.xml"); // Load the configuration of the tracker
   tracker.getCameraParameters(cam);   // Get the camera parameters used by the tracker (from the configuration file).
   tracker.loadModel("cube.cao");      // Load the 3d model in cao format. No 3rd party library is required
-  tracker.initClick(I, "cube.init");  // Initialise manually the pose by clicking on the image points associated to the 3d points containned in the cube.init file.
+  tracker.initClick(I, "cube.init");  // Initialise manually the pose by clicking on the image points associated to the 3d points contained in the cube.init file.
 
-  while(true){
+  while (true) {
     // Acquire a new image
     vpDisplay::display(I);
     tracker.track(I);     // Track the object on this image
diff --git a/vision/sample-vpKeyPoint-2.cpp b/vision/sample-vpKeyPoint-2.cpp
index a386155..3fed7d3 100644
--- a/vision/sample-vpKeyPoint-2.cpp
+++ b/vision/sample-vpKeyPoint-2.cpp
@@ -5,8 +5,9 @@
 #include <visp3/vision/vpHomography.h>
 #include <visp3/core/vpCameraParameters.h>
 
-#if (VISP_HAVE_OPENCV_VERSION >= 0x020101)
-int main() {
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_FEATURES2D)
+int main()
+{
   vpImage<unsigned char> IRef, I, IMatching;
   vpImageIo::read(IRef, "box.png");
   vpImageIo::read(I, "box_in_scene.png");
@@ -16,7 +17,7 @@ int main() {
   //Hamming distance must be used with ORB
   const std::string matcherName = "BruteForce-Hamming";
   vpKeyPoint::vpFilterMatchingType filterType =
-      vpKeyPoint::ratioDistanceThreshold;
+    vpKeyPoint::ratioDistanceThreshold;
 
   vpKeyPoint keypoint(detectorName, extractorName, matcherName, filterType);
   keypoint.setMatchingRatioThreshold(0.8);
@@ -43,7 +44,7 @@ int main() {
   vpDisplay::display(IMatching);
 
   //Compute a Ransac homography to find the box
-  vpCameraParameters cam(600, 600, I.getWidth()/2, I.getHeight()/2);
+  vpCameraParameters cam(600, 600, I.getWidth() / 2, I.getHeight() / 2);
   vpHomography H;
 
   //List of keypoints coordinates in normalized camera frame in reference image
@@ -64,12 +65,12 @@ int main() {
   double residual;
   //At least 50% of the matched points must have a positive vote to consider
   //the solution picked valid
-  unsigned int nb_inliers_consensus = (unsigned int) mPref_x.size() / 2;
+  unsigned int nb_inliers_consensus = (unsigned int)mPref_x.size() / 2;
   //Maximum error (in meter) allowed to consider a point as an inlier
   double ransac_threshold = 2.0 / cam.get_px();
   vpHomography::ransac(mPref_x, mPref_y, mPcur_x, mPcur_y, H, inliers,
-      residual, nb_inliers_consensus, ransac_threshold,
-      true);
+    residual, nb_inliers_consensus, ransac_threshold,
+    true);
 
 
   //Defines the 4 corners of the box in the reference and the current images
@@ -101,7 +102,8 @@ int main() {
   return 0;
 }
 #else
-int main() {
+int main()
+{
   return 0;
 }
 #endif
diff --git a/vision/sample-vpKeyPoint-3.cpp b/vision/sample-vpKeyPoint-3.cpp
index 7c2e9a0..96e4aab 100644
--- a/vision/sample-vpKeyPoint-3.cpp
+++ b/vision/sample-vpKeyPoint-3.cpp
@@ -3,7 +3,7 @@
 
 int main()
 {
-#if (VISP_HAVE_OPENCV_VERSION >= 0x020300)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_FEATURES2D)
   vpImage<unsigned char> Irefrence;
   vpImage<unsigned char> Icurrent;
 
diff --git a/vision/sample-vpKeyPoint-4.cpp b/vision/sample-vpKeyPoint-4.cpp
index 9196d7b..b9c0e94 100644
--- a/vision/sample-vpKeyPoint-4.cpp
+++ b/vision/sample-vpKeyPoint-4.cpp
@@ -4,7 +4,7 @@
 
 int main()
 {
-#if (VISP_HAVE_OPENCV_VERSION >= 0x020300)
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_FEATURES2D)
   vpImage<unsigned char> Ireference;
   vpImage<unsigned char> Icurrent;
 
@@ -16,8 +16,7 @@ int main()
 
   //Select a part of the image by clincking on two points which define a rectangle
   vpImagePoint corners[2];
-  for (int i=0 ; i < 2 ; i++)
-  {
+  for (int i = 0; i < 2; i++) {
     vpDisplay::getClick(Ireference, corners[i]);
   }
 
@@ -31,8 +30,7 @@ int main()
   //Then grab another image which represents the current image Icurrent
 
   //Select a part of the image by clincking on two points which define a rectangle
-  for (int i=0 ; i < 2 ; i++)
-  {
+  for (int i = 0; i < 2; i++) {
     vpDisplay::getClick(Icurrent, corners[i]);
   }
 
diff --git a/vision/sample-vpKeyPoint.cpp b/vision/sample-vpKeyPoint.cpp
index d882eb8..aa52ab6 100644
--- a/vision/sample-vpKeyPoint.cpp
+++ b/vision/sample-vpKeyPoint.cpp
@@ -3,8 +3,9 @@
 #include <visp3/io/vpImageIo.h>
 #include <visp3/vision/vpKeyPoint.h>
 
-#if (VISP_HAVE_OPENCV_VERSION >= 0x020101)
-int main() {
+#if defined(VISP_HAVE_OPENCV) && defined(HAVE_OPENCV_IMGPROC) && defined(HAVE_OPENCV_FEATURES2D)
+int main()
+{
   //Test Matching side by side
   vpImage<unsigned char> IRef, I, IMatching;
   vpImageIo::read(IRef, "box.png");
@@ -15,7 +16,7 @@ int main() {
   //Hamming distance must be used with ORB
   const std::string matcherName = "BruteForce-Hamming";
   vpKeyPoint::vpFilterMatchingType filterType =
-      vpKeyPoint::ratioDistanceThreshold;
+    vpKeyPoint::ratioDistanceThreshold;
 
   vpKeyPoint keypoint(detectorName, extractorName, matcherName, filterType);
 
@@ -46,7 +47,8 @@ int main() {
   return 0;
 }
 #else
-int main() {
+int main()
+{
   return 0;
 }
 #endif