How to crop a single desired face out of multiple detected faces in java.

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here is my code which detects and crops the image: 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;

public class FaceDetections {

public static void main(String[] args)
{

    System.loadLibrary(Core.NATIVE_LIBRARY_NAME);


    CascadeClassifier faceDetector = new CascadeClassifier();

faceDetector.load("C:\myproject\opencv\sources\data\haarcascades\haarcascade_frontalface_alt.xml"); System.out.println ( "Working" ); // Input image Mat image = Imgcodecs.imread("D:\input4.jpg");

    // Detecting faces
    MatOfRect faceDetections = new MatOfRect();
    faceDetector.detectMultiScale(image, faceDetections);

    // Creating a rectangular box showing faces detected
    Rect rectCrop=null;
    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));
        rectCrop = new Rect(rect.x, rect.y, rect.width, rect.height);
    }

    // Saving the output image
    String filename = "Ouput4.jpg";
    Imgcodecs.imwrite("D:\\"+filename, image);

    Mat markedImage = new Mat(image,rectCrop);
    Imgcodecs.imwrite("D:\\cropimage_914.jpg",markedImage );
}

}