content: 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.imgcodecs.Imgcodecs;
  import org.opencv.imgproc.Imgproc;
  import org.opencv.objdetect.CascadeClassifier;
  
  /*
   * Detects faces in an image, draws boxes around them, and writes the results
   * to "faceDetection.png".
   */
  public class DetectFaceDemo {
      public void run() {
          System.out.println("\nRunning DetectFaceDemo");
  
          // Create a face detector from the cascade file in the resources
          // directory.
          CascadeClassifier faceDetector = new CascadeClassifier(getClass()
                  .getResource("/lbpcascade_frontalface.xml").getPath());
          Mat image = Imgcodecs.imread(getClass().getResource(
                  "/AverageMaleFace.jpg").getPath());
  
          // Detect faces in the image.
          // MatOfRect is a special container class for Rect.
          MatOfRect faceDetections = new MatOfRect();
          faceDetector.detectMultiScale(image, faceDetections);
  
          System.out.println(String.format("Detected %s faces",
                  faceDetections.toArray().length));
  
          // Draw a bounding box around each face.
          for (Rect rect : faceDetections.toArray()) {
              Imgproc.rectangle(image, new Point(rect.x, rect.y), new Point(rect.x
                      + rect.width, rect.y + rect.height), new Scalar(0, 255, 0));
          }
  
          // Save the visualized detection.
          String filename = "faceDetection.png";
          System.out.println(String.format("Writing %s", filename));
          Imgcodecs.imwrite(filename, image);
      }
  }
  