Tutorial Adding Images

doc/tutorials/core/adding_images/adding_images.markdown

@@ -1,13 +1,16 @@
 Adding (blending) two images using OpenCV {#tutorial_adding_images}
 =========================================
 
+@prev_tutorial{tutorial_mat_operations}
+@next_tutorial{tutorial_basic_linear_transform}
+
 Goal
 ----
 
 In this tutorial you will learn:
 
 -   what is *linear blending* and why it is useful;
--   how to add two images using @ref cv::addWeighted
+-   how to add two images using **addWeighted()**
 
 Theory
 ------
@@ -28,33 +31,83 @@ eh?)
 Source Code
 -----------
 
+@add_toggle_cpp
 Download the source code from
-[here](https://github.com/opencv/opencv/tree/master/samples/cpp/tutorial_code/core/AddingImages/AddingImages.cpp).
+[here](https://raw.githubusercontent.com/opencv/opencv/master/samples/cpp/tutorial_code/core/AddingImages/AddingImages.cpp).
 @include cpp/tutorial_code/core/AddingImages/AddingImages.cpp
+@end_toggle
+
+@add_toggle_java
+Download the source code from
+[here](https://raw.githubusercontent.com/opencv/opencv/master/samples/java/tutorial_code/core/AddingImages/AddingImages.java).
+@include java/tutorial_code/core/AddingImages/AddingImages.java
+@end_toggle
+
+@add_toggle_python
+Download the source code from
+[here](https://raw.githubusercontent.com/opencv/opencv/master/samples/python/tutorial_code/core/AddingImages/adding_images.py).
+@include python/tutorial_code/core/AddingImages/adding_images.py
+@end_toggle
 
 Explanation
 -----------
 
--#  Since we are going to perform:
+Since we are going to perform:
+
+\f[g(x) = (1 - \alpha)f_{0}(x) + \alpha f_{1}(x)\f]
+
+We need two source images (\f$f_{0}(x)\f$ and \f$f_{1}(x)\f$). So, we load them in the usual way:
+@add_toggle_cpp
+@snippet cpp/tutorial_code/core/AddingImages/AddingImages.cpp load
+@end_toggle
+
+@add_toggle_java
+@snippet java/tutorial_code/core/AddingImages/AddingImages.java load
+@end_toggle
+
+@add_toggle_python
+@snippet python/tutorial_code/core/AddingImages/adding_images.py load
+@end_toggle
+
+We used the following images: [LinuxLogo.jpg](https://raw.githubusercontent.com/opencv/opencv/master/samples/data/LinuxLogo.jpg) and [WindowsLogo.jpg](https://raw.githubusercontent.com/opencv/opencv/master/samples/data/WindowsLogo.jpg)
+
+@warning Since we are *adding* *src1* and *src2*, they both have to be of the same size
+(width and height) and type.
+
+Now we need to generate the `g(x)` image. For this, the function **addWeighted()** comes quite handy:
+
+@add_toggle_cpp
+@snippet cpp/tutorial_code/core/AddingImages/AddingImages.cpp blend_images
+@end_toggle
 
-    \f[g(x) = (1 - \alpha)f_{0}(x) + \alpha f_{1}(x)\f]
+@add_toggle_java
+@snippet java/tutorial_code/core/AddingImages/AddingImages.java blend_images
+@end_toggle
 
-    We need two source images (\f$f_{0}(x)\f$ and \f$f_{1}(x)\f$). So, we load them in the usual way:
-    @snippet cpp/tutorial_code/core/AddingImages/AddingImages.cpp load
+@add_toggle_python
+@snippet python/tutorial_code/core/AddingImages/adding_images.py blend_images
+Numpy version of above line (but cv2 function is around 2x faster):
+\code{.py}
+    dst = np.uint8(alpha*(img1)+beta*(img2))
+\endcode
+@end_toggle
 
-    **warning**
+since **addWeighted()**  produces:
+\f[dst = \alpha \cdot src1 + \beta \cdot src2 + \gamma\f]
+In this case, `gamma` is the argument \f$0.0\f$ in the code above.
 
-    Since we are *adding* *src1* and *src2*, they both have to be of the same size (width and
-    height) and type.
+Create windows, show the images and wait for the user to end the program.
+@add_toggle_cpp
+@snippet cpp/tutorial_code/core/AddingImages/AddingImages.cpp display
+@end_toggle
 
--#  Now we need to generate the `g(x)` image. For this, the function @ref cv::addWeighted comes quite handy:
-    @snippet cpp/tutorial_code/core/AddingImages/AddingImages.cpp blend_images
-    since @ref cv::addWeighted  produces:
-    \f[dst = \alpha \cdot src1 + \beta \cdot src2 + \gamma\f]
-    In this case, `gamma` is the argument \f$0.0\f$ in the code above.
+@add_toggle_java
+@snippet java/tutorial_code/core/AddingImages/AddingImages.java display
+@end_toggle
 
--#  Create windows, show the images and wait for the user to end the program.
-    @snippet cpp/tutorial_code/core/AddingImages/AddingImages.cpp display
+@add_toggle_python
+@snippet python/tutorial_code/core/AddingImages/adding_images.py display
+@end_toggle
 
 Result
 ------

doc/tutorials/core/table_of_content_core.markdown

@@ -40,6 +40,8 @@ understanding how to manipulate the images on a pixel level.
 
 -   @subpage tutorial_adding_images
 
+    *Languages:* C++, Java, Python
+
     *Compatibility:* \> OpenCV 2.0
 
     *Author:* Ana Huamán

samples/cpp/tutorial_code/core/AddingImages/AddingImages.cpp

@@ -3,7 +3,6 @@
  * @brief Simple linear blender ( dst = alpha*src1 + beta*src2 )
  * @author OpenCV team
  */
-
 #include "opencv2/imgcodecs.hpp"
 #include "opencv2/highgui.hpp"
 #include <iostream>
@@ -24,7 +23,7 @@ int main( void )
    /// Ask the user enter alpha
    cout << " Simple Linear Blender " << endl;
    cout << "-----------------------" << endl;
-   cout << "* Enter alpha [0-1]: ";
+   cout << "* Enter alpha [0.0-1.0]: ";
    cin >> input;
 
    // We use the alpha provided by the user if it is between 0 and 1

samples/java/tutorial_code/core/AddingImages/AddingImages.java

@@ -0,0 +1,51 @@
+import org.opencv.core.*;
+import org.opencv.highgui.HighGui;
+import org.opencv.imgcodecs.Imgcodecs;
+
+import java.util.Locale;
+import java.util.Scanner;
+
+class AddingImagesRun{
+    public void run() {
+        double alpha = 0.5; double beta; double input;
+
+        Mat src1, src2, dst = new Mat();
+
+        System.out.println(" Simple Linear Blender ");
+        System.out.println("-----------------------");
+        System.out.println("* Enter alpha [0.0-1.0]: ");
+        Scanner scan = new Scanner( System.in ).useLocale(Locale.US);
+        input = scan.nextDouble();
+
+        if( input >= 0.0 && input <= 1.0 )
+            alpha = input;
+
+        //! [load]
+        src1 = Imgcodecs.imread("../../images/LinuxLogo.jpg");
+        src2 = Imgcodecs.imread("../../images/WindowsLogo.jpg");
+        //! [load]
+
+        if( src1.empty() == true ){ System.out.println("Error loading src1"); return;}
+        if( src2.empty() == true ){ System.out.println("Error loading src2"); return;}
+
+        //! [blend_images]
+        beta = ( 1.0 - alpha );
+        Core.addWeighted( src1, alpha, src2, beta, 0.0, dst);
+        //! [blend_images]
+
+        //![display]
+        HighGui.imshow("Linear Blend", dst);
+        HighGui.waitKey(0);
+        //![display]
+
+        System.exit(0);
+    }
+}
+
+public class AddingImages {
+    public static void main(String[] args) {
+        // Load the native library.
+        System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
+        new AddingImagesRun().run();
+    }
+}

samples/python/tutorial_code/core/AddingImages/adding_images.py

@@ -0,0 +1,35 @@
+from __future__ import print_function
+import sys
+
+import cv2
+
+alpha = 0.5
+
+print(''' Simple Linear Blender
+-----------------------
+* Enter alpha [0.0-1.0]: ''')
+if sys.version_info >= (3, 0): # If Python 3.x
+    input_alpha = float(input())
+else:
+    input_alpha = float(raw_input())
+if 0 <= alpha <= 1:
+    alpha = input_alpha
+## [load]
+src1 = cv2.imread('../../../../data/LinuxLogo.jpg')
+src2 = cv2.imread('../../../../data/WindowsLogo.jpg')
+## [load]
+if src1 is None:
+    print ("Error loading src1")
+    exit(-1)
+elif src2 is None:
+    print ("Error loading src2")
+    exit(-1)
+## [blend_images]
+beta = (1.0 - alpha)
+dst = cv2.addWeighted(src1, alpha, src2, beta, 0.0)
+## [blend_images]
+## [display]
+cv2.imshow('dst', dst)
+cv2.waitKey(0)
+## [display]
+cv2.destroyAllWindows()