Main.java

import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.highgui.Highgui;
import org.opencv.highgui.VideoCapture;
import org.opencv.objdetect.CascadeClassifier;

class DetectFaceDemo {
  public void run() {
		System.out.println("\nRunning DetectFaceDemo");
		CascadeClassifier faceDetector = new CascadeClassifier("lbpcascade_frontalface.xml");
		Mat image = new Mat();
		VideoCapture capture = new VideoCapture(0);
		while (capture.grab()) {
			capture.retrieve(image);
			if (image != null) {
				MatOfRect faceDetections = new MatOfRect();
				faceDetector.detectMultiScale(image, faceDetections);

				System.out.println(String.format("Detected %s faces",
						faceDetections.toArray().length));

				if (faceDetections.toArray().length != 0) {

					for (Rect rect : faceDetections.toArray()) {

						Core.rectangle(image, new Point(rect.x, rect.y),
								new Point(rect.x + rect.width, rect.y
										+ rect.height), new Scalar(0, 255, 0));
						image = image.adjustROI(rect.y, rect.y + rect.height, rect.x, rect.x+rect.width);
						break;
					}
					System.out.println(image.width() + " " + image.height());
					String filename = "faceDetection.jpg";
					System.out.println(String.format("Writing %s", filename));
					Highgui.imwrite(filename, image);
					break;
				}
			}
		}
	}
}

public class Main {

	public static void main(String[] args) {
		try {
			System.loadLibrary("opencv_java249");
			new DetectFaceDemo().run();
		} catch (Exception e) {
			e.printStackTrace();
		}

	}
}