How to implement blur (averaging) in OpenCV using Java?

JavaObject Oriented ProgrammingProgramming

You can blur an image by filtering it using a low-pass filter, this removes high frequency content (noise, edges) from an image.

Averaging is one of the blurring techniques provided by OpenCV, this replaces the central element with the average of all the pixels in the kernel area

You can filter/blur an image by this technique using the blur() or, boxFilter() methods, the blur() method accepts −

  • Two Mat objects representing the source and destination images.

  • A Size object representing the size of the kernel.

  • An integer variable representing the anchor point.

  • An integer variable of representing the type of the border to be used to the output.


import java.awt.Image;
import java.awt.image.BufferedImage;
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.Point;
import org.opencv.core.Size;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
public class NormalizedBoxExample extends Application {
   public void start(Stage stage) throws IOException {
      //Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      //Reading image data
      String file ="D:\\Images\\lamma2.jpg";
      Mat src = Imgcodecs.imread(file);
      //Creating destination matrix
      Mat dst = new Mat(src.rows(), src.cols(), src.type());
      // Creating the Size and Point objects
      Size size = new Size(45, 45);
      Point point = new Point(20, 30);
      // Applying Blur effect on the Image
      Imgproc.blur(src, dst, size, point, Core.BORDER_DEFAULT);
      //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);
      //Setting the Scene object
      Group root = new Group(imageView);
      Scene scene = new Scene(root, 595, 400);
      stage.setTitle("Normalized Blur Example");
   public static void main(String args[]) {

Input Image


On executing the above program generates the following output −

Published on 09-Apr-2020 08:34:24