How to add noise to an image using Java OpenCV library?

To add noise to a given image using OpenCV −

• Read the contents of the given image to a Mat object.

• Create two more empty matrices to store the noise and the resultant matrices.

• Create two MatOfDouble matrices to store mean and standard deviation.

• Get the mean and standard deviation values using the meanStdDev() method.

• Create a matrix with random elements (to store the noise) using the randn() method.

• To this method pass the above-created source, mean and standard deviation objects.

Finally, add the noise matrix and source matrix and save as destination.

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.Mat;
import org.opencv.core.MatOfDouble;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
public class AddingNoise extends Application {
   public void start(Stage stage) throws IOException {
      //Loading the OpenCV core library
      System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
      //Reading the Image from the file
      String file ="D://images//elephant.jpg";
      Mat src = Imgcodecs.imread(file);
      System.out.println("Image Loaded");
      //Creating destination matrix
      Mat dst = new Mat(src.rows(), src.cols(), src.type());
      //Creating a matrix for the noise
      Mat noise = new Mat(src.rows(), src.cols(), src.type());
      //Calculating the mean and standard deviation
      MatOfDouble mean = new MatOfDouble();
      MatOfDouble dev = new MatOfDouble();
      Core.meanStdDev(src, mean, dev);
      //Filling the noise matrix
      Core.randn(noise, mean.get(0,0)[0], dev.get(0,0)[0]);
      //Adding noise to the destination
      Core.add(src, noise, 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("Adding Noise Example");
      stage.setScene(scene);
      stage.show();
   }
   public static void main(String args[]) {
      launch(args);
   }
}

Input Image

Output

On executing, the above program generates the following output −