The HighGui class of the org.opencv.highgui package allows you to create and manipulate windows and display them. You can display an image in a window using the imshow() method of this class. This method accepts two parameters−
A string variable representing the name of the window.
A Mat object representing the contents of an image.
It is recommended to invoke the waitKey() method after imshow().
Example
The following example reads an image, converts it into a grayscale image, detects the edges in it and displays all the three images (original, gray-scale and, edges) in windows using HighGui.
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.highgui.HighGui;
import org.opencv.imgcodecs.Imgcodecs;
import org.opencv.imgproc.Imgproc;
public class ImshowExample {
public static void main(String args[]) {
//Loading the OpenCV core library
System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
//Reading the Image from the file
Mat src = Imgcodecs.imread("D://images//window.jpg");
HighGui.imshow("Original Image", src);
//Converting color to gray scale
Mat gray = new Mat(src.rows(), src.cols(), src.type());
Imgproc.cvtColor(src, gray, Imgproc.COLOR_RGB2GRAY);
HighGui.imshow("Gray Scale Image", gray);
//Applying canny
Mat dst = new Mat(src.rows(), src.cols(), src.type());
Imgproc.Canny(gray, dst, 100, 100*3);
HighGui.imshow("Edges", dst);
HighGui.waitKey();
}
}Output
On executing, the above program generates three windows as shown below −
Original image −

Grayscale image −

Image with edges highlighted −
