OpenCV Tutorial
Types of Images
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OpenCV - Grayscale to Binary
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.apppcation.Apppcation; 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; pubpc class GrayScaleToBinary extends Apppcation { @Override pubpc 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(); } pubpc WritableImage loadAndConvert() throws Exception { // Loading the OpenCV core pbrary 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 = imageCodecs.imread(input); // Creating the destination matrix Mat dst = new Mat(); // Converting to binary image... Imgproc.threshold(src, dst, 200, 500, Imgproc.THRESH_BINARY); // Extracting data from the transformed image (dst) byte[] data1 = new byte[dst.rows() * dst.cols() * (int)(dst.elemSize())]; dst.get(0, 0, data1); // Creating Buffered image using the data BufferedImage bufImage = new BufferedImage(dst.cols(),dst.rows(), BufferedImage.TYPE_BYTE_BINARY); // Setting the data elements to the image bufImage.getRaster().setDataElements(0, 0, dst.cols(), dst.rows(), data1); // Creating a Writable image WritableImage writableImage = SwingFXUtils.toFXImage(bufImage, null); System.out.println("Converted to binary"); return writableImage; } pubpc 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.
![Sample Image](/opencv/images/sample_image.jpg)
Output Image
On executing the program, you will get the following output.
![GrayScale to Binary](/opencv/images/grayscale_to_binary.jpg)