Merge remote-tracking branch 'upstream/3.4' into merge-3.4

samples/cpp/stitching_detailed.cpp

@@ -82,7 +82,7 @@ static void printUsage()
         "\nMotion Estimation Flags:\n"
         "  --work_megapix <float>\n"
         "      Resolution for image registration step. The default is 0.6 Mpx.\n"
-        "  --features (surf|orb)\n"
+        "  --features (surf|orb|sift)\n"
         "      Type of features used for images matching. The default is surf.\n"
         "  --matcher (homography|affine)\n"
         "      Matcher used for pairwise image matching.\n"
@@ -430,6 +430,9 @@ int main(int argc, char* argv[])
     {
         finder = makePtr<OrbFeaturesFinder>();
     }
+    else if (features_type == "sift") {
+        finder = makePtr<SiftFeaturesFinder>();
+    }
     else
     {
         cout << "Unknown 2D features type: '" << features_type << "'.\n";

samples/cpp/train_HOG.cpp

@@ -204,7 +204,7 @@ int main( int argc, char** argv )
     const char* keys =
     {
         "{help h|     | show help message}"
-        "{pd    |     | path of directory contains possitive images}"
+        "{pd    |     | path of directory contains positive images}"
         "{nd    |     | path of directory contains negative images}"
         "{td    |     | path of directory contains test images}"
         "{tv    |     | test video file name}"

samples/cpp/tutorial_code/ml/introduction_to_pca/introduction_to_pca.cpp

@@ -1,6 +1,6 @@
 /**
  * @file introduction_to_pca.cpp
- * @brief This program demonstrates how to use OpenCV PCA to extract the orienation of an object
+ * @brief This program demonstrates how to use OpenCV PCA to extract the orientation of an object
  * @author OpenCV team
  */
 

samples/cpp/warpPerspective_demo.cpp

@@ -26,7 +26,7 @@ static void help(char** argv)
          "\tESC, q - quit the program\n"
          "\tr - change order of points to rotate transformation\n"
          "\tc - delete selected points\n"
-         "\ti - change order of points to invers transformation \n"
+         "\ti - change order of points to inverse transformation \n"
          "\nUse your mouse to select a point and move it to see transformation changes" << endl;
 }