问EMGU CV异常

EN

        _cascadeClassifier = new CascadeClassifier(Application.StartupPath + "/haarcascade_frontalface_default.xml");
        using (var imageFrame = _capture.QueryFrame().ToImage<Bgr, Byte>())
        {
            if (imageFrame != null)
            {
                var grayframe = imageFrame.Convert<Gray, byte>();
                var faces = _cascadeClassifier.DetectMultiScale(grayframe, 1.1, 10, Size.Empty); //the actual face detection happens here
                foreach (var face in faces)
                {
                    imageFrame.Draw(face, new Bgr(Color.BurlyWood), 3); //the detected face(s) is highlighted here using a box that is drawn around it/them

                }
            }
            imgCamUser.Image = imageFrame;
        }