Explain OpenCV Laplacian Transformation using java Example

The Laplacian transform on an image highlights the regions where there is a rapid intensity change. Therefore, it is used to detect edges.

The Laplacian() method of the Imgproc class applies Laplacian Transform on the given image, this method accepts −

• Two Mat objects representing the source and destination images.

• Four integer variables representing the depth, size, scale and, delta values of the transform.

• An integer value representing the border.

Example

import java.awt.Image; import java.awt.image.BufferedImage; import java.io.IOException; import javafx.application.Application; import javafx.embed.swing.SwingFXUtils; import javafx.scene.Group; import javafx.scene.Scene; import javafx.scene.image.ImageView; import javafx.scene.image.WritableImage; import javafx.stage.Stage; import org.opencv.core.Core; import org.opencv.core.CvType; import org.opencv.core.Mat; import org.opencv.highgui.HighGui; import org.opencv.imgcodecs.Imgcodecs; import org.opencv.imgproc.Imgproc; public class LaplacianTransform extends Application {    public void start(Stage stage) throws IOException {       //Loading OpenCV library       System.loadLibrary(Core.NATIVE_LIBRARY_NAME);       //Creating Mat objects to store source and destination images       Mat src = new Mat();       Mat dst = new Mat();       //Reading Image       src = Imgcodecs.imread("D:\Images\road3.jpg");       //Applying Laplacian transform       Imgproc.Laplacian( src, dst, CvType.CV_16S, 3, 1, 0, Core.BORDER_DEFAULT );       //Imgproc.Laplacian(src, dst, ddepth, ksize, scale, delta, borderType);       // converting back to CV_8U       Core.convertScaleAbs( dst, dst );       //Converting matrix to JavaFX writable image       Image img = HighGui.toBufferedImage(dst);       WritableImage writableImage= SwingFXUtils.toFXImage((BufferedImage) img, null);       //Setting the image view       ImageView imageView = new ImageView(writableImage);       imageView.setX(10);       imageView.setY(10);       imageView.setFitWidth(575);       imageView.setPreserveRatio(true);       //Setting the Scene object       Group root = new Group(imageView);       Scene scene = new Scene(root, 595, 400);       stage.setTitle("Laplacian Transform");       stage.setScene(scene);       stage.show();    }    public static void main(String args[]) {       launch(args);    } }

Input Image

Output

On executing, the above program generates the following windows −