OpenCV - Reading Image as BGR


The following program demonstrates how to read a colored image as BGR type image and display it using JavaFX window. In here, we have read the image by passing the flag IMREAD_COLOR to the method imread() along with the String holding the path of a colored image.

import java.awt.image.BufferedImage;

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

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 ReadingAsColored extends Application {
   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

      // setting the fit height and width of the image view
      // Setting the preserve ratio of the image view
      // 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("Reading as colored image");

      // Adding scene to the stage
      // Displaying the contents of the stage;
   public WritableImage loadAndConvert() throws Exception {     
      // Loading the OpenCV core library
      System.loadLibrary( Core.NATIVE_LIBRARY_NAME );
      String input = "C:/EXAMPLES/OpenCV/sample.jpg";
      Mat dst = new Mat();

      // Reading the image
      Mat src = Imgcodecs.imread(input, Imgcodecs.IMREAD_COLOR);

      byte[] data1 = new byte[src.rows() * src.cols() * (int)(src.elemSize())]; 
      src.get(0, 0, data1);
      // Creating the buffered image
      BufferedImage bufImage = new BufferedImage(src.cols(),src.rows(), 

      // Setting the data elements to the image 
      bufImage.getRaster().setDataElements(0, 0, src.cols(), src.rows(), data1);

      // Creating a WritableImage
      WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null);

      System.out.println("Image read");
      return writableImage;
   public static void main(String args[]) throws Exception {

Input Image

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

Sample Image

Output Image

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

BGR Output Image