OpenCV - Median Blur


The Median blur operation is similar to the other averaging methods. Here, the central element of the image is replaced by the median of all the pixels in the kernel area. This operation processes the edges while removing the noise.

You can perform this operation on an image using the medianBlur() method of the imgproc class. Following is the syntax of this method −

medianBlur(src, dst, ksize)

This method accepts the following parameters −

  • src − A Mat object representing the source (input image) for this operation.

  • dst − A Mat object representing the destination (output image) for this operation.

  • ksize − A Size object representing the size of the kernel.


The following program demonstrates how to perform the median blur operation on an image.

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;

public class MedianBlurTest {
   public static void main(String args[]) {
      // Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );

      // Reading the Image from the file and storing it in to a Matrix object
      String file ="C:/EXAMPLES/OpenCV/sample.jpg";
      Mat src = Imgcodecs.imread(file);

      // Creating an empty matrix to store the result
      Mat dst = new Mat();

      // Applying MedianBlur on the Image
      Imgproc.medianBlur(src, dst, 15);

      // Writing the image
      Imgcodecs.imwrite("E:/OpenCV/chap9/median.jpg", dst);

      System.out.println("Image Processed");

Assume that following is the input image sample.jpg specified in the above program.

Sample Image


On executing the program, you will get the following output −

Image Processed

If you open the specified path, you can observe the output image as follows −

Median Blur