Merge pull request #16276 from themechanicalcoder:video-tutorial

* Added java code for meanshift and optical_flow

* added java code for module video

* added appropriate spaces in codes

* converted absolute path to command line arguments

* added spaces at appropriate places

doc/tutorials/video/meanshift/meanshift.markdown

@@ -57,6 +57,14 @@ low light, low light values are discarded using **cv.inRange()** function.
     @include samples/python/tutorial_code/video/meanshift/meanshift.py
 @end_toggle
 
+@add_toggle_java
+-   **Downloadable code**: Click
+    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/meanshift/MeanshiftDemo.java)
+
+-   **Code at glance:**
+    @include  samples/java/tutorial_code/video/meanshift/MeanshiftDemo.java
+@end_toggle
+
 Three frames in a video I used is given below:
 
 ![image](images/meanshift_result.jpg)
@@ -98,6 +106,14 @@ parameters (used to be passed as search window in next iteration). See the code
     @include samples/python/tutorial_code/video/meanshift/camshift.py
 @end_toggle
 
+@add_toggle_java
+-   **Downloadable code**: Click
+    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/meanshift/CamshiftDemo.java)
+
+-   **Code at glance:**
+    @include  samples/java/tutorial_code/video/meanshift/CamshiftDemo.java
+@end_toggle
+
 Three frames of the result is shown below:
 
 ![image](images/camshift_result.jpg)

doc/tutorials/video/optical_flow/optical_flow.markdown

@@ -109,6 +109,15 @@ below:
     @include samples/python/tutorial_code/video/optical_flow/optical_flow.py
 @end_toggle
 
+
+@add_toggle_java
+-   **Downloadable code**: Click
+    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/optical_flow/OpticalFlowDemo.java)
+
+-   **Code at glance:**
+    @include samples/java/tutorial_code/video/optical_flow/OpticalFlowDemo.java
+@end_toggle
+
 (This code doesn't check how correct are the next keypoints. So even if any feature point disappears
 in image, there is a chance that optical flow finds the next point which may look close to it. So
 actually for a robust tracking, corner points should be detected in particular intervals. OpenCV
@@ -151,6 +160,15 @@ corresponds to Value plane. See the code below:
 @end_toggle
 
 
+@add_toggle_java
+-   **Downloadable code**: Click
+    [here](https://github.com/opencv/opencv/tree/3.4/samples/java/tutorial_code/video/optical_flow/OpticalFlowDenseDemo.java)
+
+-   **Code at glance:**
+    @include samples/java/tutorial_code/video/optical_flow/OpticalFlowDenseDemo.java
+@end_toggle
+
+
 See the result below:
 
 ![image](images/opticalfb.jpg)

doc/tutorials/video/table_of_content_video.markdown

@@ -17,12 +17,12 @@ tracking and foreground extractions.
 
 -   @subpage tutorial_meanshift
 
-    *Languages:* C++, Python
+    *Languages:* C++, Java, Python
 
     Learn how to use the Meanshift and Camshift algorithms to track objects in videos.
 
 -   @subpage tutorial_optical_flow
 
-    *Languages:* C++, Python
+    *Languages:* C++, Java, Python
 
     We will learn how to use optical flow methods to track sparse features or to create a dense representation.