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

diff --cc doc/tutorials/introduction/display_image/display_image.markdown
index ba55058,ee6c200..72635a3
--- 1/doc/tutorials/introduction/display_image/display_image.markdown
--- 2/doc/tutorials/introduction/display_image/display_image.markdown
+++ b/doc/tutorials/introduction/display_image/display_image.markdown
@@@ -13,10 -13,22 +13,22 @@@ In this tutorial you will learn how to
  Source Code
  -----------
  
- Download the source code from
- [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/introduction/display_image/display_image.cpp).
+ @add_toggle_cpp
+ -   **Downloadable code**: Click
 -    [here](https://github.com/opencv/opencv/tree/3.4/samples/cpp/tutorial_code/introduction/display_image/display_image.cpp)
++    [here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/introduction/display_image/display_image.cpp)
+ 
+ -   **Code at glance:**
+     @include samples/cpp/tutorial_code/introduction/display_image/display_image.cpp
+ @end_toggle
+ 
+ @add_toggle_python
+ -   **Downloadable code**: Click
 -    [here](https://github.com/opencv/opencv/tree/3.4/samples/python/tutorial_code/introduction/display_image/display_image.py)
++    [here](https://github.com/opencv/opencv/tree/master/samples/python/tutorial_code/introduction/display_image/display_image.py)
+ 
+ -   **Code at glance:**
+     @include samples/python/tutorial_code/introduction/display_image/display_image.py
+ @end_toggle
  
- @include cpp/tutorial_code/introduction/display_image/display_image.cpp
  
  Explanation
  -----------

diff --cc modules/dnn/src/dnn.cpp
Simple merge

diff --cc modules/dnn/src/init.cpp
Simple merge

diff --cc modules/dnn/src/layers/fully_connected_layer.cpp
index 9fdcd32,3f3b62b..b17391f
--- 1/modules/dnn/src/layers/fully_connected_layer.cpp
--- 2/modules/dnn/src/layers/fully_connected_layer.cpp
+++ b/modules/dnn/src/layers/fully_connected_layer.cpp
@@@ -131,9 -145,9 +148,10 @@@ public
      virtual bool supportBackend(int backendId) CV_OVERRIDE
      {
          return backendId == DNN_BACKEND_OPENCV ||
 +               backendId == DNN_BACKEND_CUDA ||
                 (backendId == DNN_BACKEND_HALIDE && haveHalide() && axis == 1) ||
-                ((backendId == DNN_BACKEND_INFERENCE_ENGINE_NN_BUILDER_2019 || backendId == DNN_BACKEND_INFERENCE_ENGINE_NGRAPH) && haveInfEngine() && axis == 1);
+                (((backendId == DNN_BACKEND_INFERENCE_ENGINE_NN_BUILDER_2019 && !blobs.empty()) ||
+                 backendId == DNN_BACKEND_INFERENCE_ENGINE_NGRAPH) && axis == 1);
      }
  
      virtual bool setActivation(const Ptr<ActivationLayer>& layer) CV_OVERRIDE

diff --cc modules/dnn/src/onnx/onnx_graph_simplifier.cpp
Simple merge

diff --cc modules/dnn/src/onnx/onnx_importer.cpp
Simple merge

diff --cc modules/dnn/src/tensorflow/tf_graph_simplifier.cpp
Simple merge

diff --cc modules/dnn/src/torch/torch_importer.cpp
Simple merge

diff --cc modules/dnn/test/test_halide_layers.cpp
Simple merge

diff --cc modules/dnn/test/test_onnx_importer.cpp
Simple merge

diff --cc modules/dnn/test/test_tf_importer.cpp
Simple merge