Several type of formal refactoring:

1. someMatrix.data -> someMatrix.prt()
2. someMatrix.data + someMatrix.step * lineIndex -> someMatrix.ptr( lineIndex )
3. (SomeType*) someMatrix.data -> someMatrix.ptr<SomeType>()
4. someMatrix.data -> !someMatrix.empty() ( or !someMatrix.data -> someMatrix.empty() ) in logical expressions

samples/cpp/tutorial_code/ImgTrans/CannyDetector_Demo.cpp

@@ -52,7 +52,7 @@ int main( int, char** argv )
   /// Load an image
   src = imread( argv[1] );
 
-  if( !src.data )
+  if( src.empty() )
     { return -1; }
 
   /// Create a matrix of the same type and size as src (for dst)

samples/cpp/tutorial_code/ImgTrans/HoughCircle_Demo.cpp

@@ -65,7 +65,7 @@ int main(int argc, char** argv)
     // Read the image
     src = imread( argv[1], 1 );
 
-    if( !src.data )
+    if( src.empty() )
     {
         std::cerr<<"Invalid input image\n";
         std::cout<<usage;

samples/cpp/tutorial_code/ImgTrans/Laplace_Demo.cpp

@@ -28,7 +28,7 @@ int main( int, char** argv )
   /// Load an image
   src = imread( argv[1] );
 
-  if( !src.data )
+  if( src.empty() )
     { return -1; }
 
   /// Remove noise by blurring with a Gaussian filter

samples/cpp/tutorial_code/ImgTrans/Sobel_Demo.cpp

@@ -28,7 +28,7 @@ int main( int, char** argv )
   /// Load an image
   src = imread( argv[1] );
 
-  if( !src.data )
+  if( src.empty() )
     { return -1; }
 
   GaussianBlur( src, src, Size(3,3), 0, 0, BORDER_DEFAULT );

samples/cpp/tutorial_code/ImgTrans/copyMakeBorder_demo.cpp

@@ -30,7 +30,7 @@ int main( int, char** argv )
   /// Load an image
   src = imread( argv[1] );
 
-  if( !src.data )
+  if( src.empty() )
     {
       printf(" No data entered, please enter the path to an image file \n");
       return -1;

samples/cpp/tutorial_code/ImgTrans/filter2D_demo.cpp

@@ -32,7 +32,7 @@ int main ( int, char** argv )
   /// Load an image
   src = imread( argv[1] );
 
-  if( !src.data )
+  if( src.empty() )
     { return -1; }
 
   /// Create window