OpenCV - Grayscale to Binary

You can use the same method mentioned in the previous chapter to convert a grayscale image to a binary image. Just pass the path for a grayscale image as input to this program.

Example

The following program demonstrates how to read a grayscale image as a binary image and display it using JavaFX window.

import java.awt.image.BufferedImage;

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

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;

public class GrayScaleToBinary extends Application {
   @Override
   public void start(Stage stage) throws Exception {
      WritableImage writableImage = loadAndConvert();
       
      // Setting the image view
      ImageView imageView = new ImageView(writableImage);

      // Setting the position of the image
      imageView.setX(10);
      imageView.setY(10);
      
      // Setting the fit height and width of the image view
      imageView.setFitHeight(400);
      imageView.setFitWidth(600);

      // Setting the preserve ratio of the image view
      imageView.setPreserveRatio(true);

      // Creating a Group object
      Group root = new Group(imageView);

      // Creating a scene object
      Scene scene = new Scene(root, 600, 400);

      // Setting title to the Stage
      stage.setTitle("Grayscale to binary image");

      // Adding scene to the stage
      stage.setScene(scene);

      // Displaying the contents of the stage
      stage.show();
   }
   public WritableImage loadAndConvert() throws Exception {
      // Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );

      // Instantiating the imagecodecs class
      Imgcodecs imageCodecs = new Imgcodecs();

      String input = "E:/OpenCV/chap7/grayscale.jpg";

      // Reading the image
      Mat src="/?originalUrl=https%3A%2F%2Fwww.tutorialspoint.com%2FimageCodecs.imread(input)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520the%2520destination%2520matrix%2520%2520%2520%2520%2520%2520Mat%2520dst%2520%3D%2520new%2520Mat()%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Converting%2520to%2520binary%2520image...%2520%2520%2520%2520%2520%2520Imgproc.threshold(src%2C%2520dst%2C%2520200%2C%2520500%2C%2520Imgproc.THRESH_BINARY)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Extracting%2520data%2520from%2520the%2520transformed%2520image%2520(dst)%2520%2520%2520%2520%2520%2520byte%5B%5D%2520data1%2520%3D%2520new%2520byte%5Bdst.rows()%2520*%2520dst.cols()%2520*%2520(int)(dst.elemSize())%5D%3B%2520%2520%2520%2520%2520%2520dst.get(0%2C%25200%2C%2520data1)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520Buffered%2520image%2520using%2520the%2520data%2520%2520%2520%2520%2520%2520BufferedImage%2520bufImage%2520%3D%2520new%2520BufferedImage(dst.cols()%2Cdst.rows()%2C%2520%2520%2520%2520%2520%2520%2520%2520%2520%2520BufferedImage.TYPE_BYTE_BINARY)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Setting%2520the%2520data%2520elements%2520to%2520the%2520image%2520%2520%2520%2520%2520%2520bufImage.getRaster().setDataElements(0%2C%25200%2C%2520dst.cols()%2C%2520dst.rows()%2C%2520data1)%3B%2520%2520%2520%2520%2520%2520%2F%2F%2520Creating%2520a%2520Writable%2520image%2520%2520%2520%2520%2520%2520WritableImage%2520writableImage%2520%3D%2520SwingFXUtils.toFXImage(bufImage%2C%2520null)%3B%2520%2520%2520%2520%2520%2520System.out.println("Converted to binary");
      return writableImage;
   }
   public static void main(String args[]) throws Exception {
      launch(args);
   }
}

Input Image

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

Output Image

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