content: /**
   * @file LaplaceDemo.java
   * @brief Sample code showing how to detect edges using the Laplace operator
   */
  
  import org.opencv.core.*;
  import org.opencv.highgui.HighGui;
  import org.opencv.imgcodecs.Imgcodecs;
  import org.opencv.imgproc.Imgproc;
  
  class LaplaceDemoRun {
  
      public void run(String[] args) {
          //! [variables]
          // Declare the variables we are going to use
          Mat src, src_gray = new Mat(), dst = new Mat();
          int kernel_size = 3;
          int scale = 1;
          int delta = 0;
          int ddepth = CvType.CV_16S;
          String window_name = "Laplace Demo";
          //! [variables]
  
          //! [load]
          String imageName = ((args.length > 0) ? args[0] : "../data/lena.jpg");
  
          src = Imgcodecs.imread(imageName, Imgcodecs.IMREAD_COLOR); // Load an image
  
          // Check if image is loaded fine
          if( src.empty() ) {
              System.out.println("Error opening image");
              System.out.println("Program Arguments: [image_name -- default ../data/lena.jpg] \n");
              System.exit(-1);
          }
          //! [load]
  
          //! [reduce_noise]
          // Reduce noise by blurring with a Gaussian filter ( kernel size = 3 )
          Imgproc.GaussianBlur( src, src, new Size(3, 3), 0, 0, Core.BORDER_DEFAULT );
          //! [reduce_noise]
  
          //! [convert_to_gray]
          // Convert the image to grayscale
          Imgproc.cvtColor( src, src_gray, Imgproc.COLOR_RGB2GRAY );
          //! [convert_to_gray]
  
          /// Apply Laplace function
          Mat abs_dst = new Mat();
          //! [laplacian]
          Imgproc.Laplacian( src_gray, dst, ddepth, kernel_size, scale, delta, Core.BORDER_DEFAULT );
          //! [laplacian]
  
          //! [convert]
          // converting back to CV_8U
          Core.convertScaleAbs( dst, abs_dst );
          //! [convert]
  
          //! [display]
          HighGui.imshow( window_name, abs_dst );
          HighGui.waitKey(0);
          //! [display]
  
          System.exit(0);
      }
  }
  
  public class LaplaceDemo {
      public static void main(String[] args) {
          // Load the native library.
          System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
          new LaplaceDemoRun().run(args);
      }
  }
  