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

diff --cc doc/tutorials/imgproc/imgtrans/distance_transformation/distance_transform.markdown
index a46f578,ca1ec47..e04ed4e
--- 1/doc/tutorials/imgproc/imgtrans/distance_transformation/distance_transform.markdown
--- 2/doc/tutorials/imgproc/imgtrans/distance_transformation/distance_transform.markdown
+++ b/doc/tutorials/imgproc/imgtrans/distance_transformation/distance_transform.markdown
@@@ -16,9 -16,23 +16,23 @@@ Theor
  Code
  ----
  
+ @add_toggle_cpp
  This tutorial code's is shown lines below. You can also download it from
-     [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp).
 -[here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp).
++[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp).
  @include samples/cpp/tutorial_code/ImgTrans/imageSegmentation.cpp
 -[here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java)
+ @end_toggle
+ 
+ @add_toggle_java
+ This tutorial code's is shown lines below. You can also download it from
 -[here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py)
++[here](https://github.com/opencv/opencv/tree/master/samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java)
+ @include samples/java/tutorial_code/ImgTrans/distance_transformation/ImageSegmentationDemo.java
+ @end_toggle
+ 
+ @add_toggle_python
+ This tutorial code's is shown lines below. You can also download it from
++[here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py)
+ @include samples/python/tutorial_code/ImgTrans/distance_transformation/imageSegmentation.py
+ @end_toggle
  
  Explanation / Result
  --------------------

diff --cc modules/calib3d/include/opencv2/calib3d.hpp
Simple merge

diff --cc modules/objdetect/include/opencv2/objdetect.hpp
Simple merge

diff --cc modules/video/src/lkpyramid.cpp
Simple merge