OpenCV facedetector

//http://www.youtube.com/user/thecplusplusguy
//This OpenCV example recognize faces from the webcam image, and draws a red rectangle around it. Make sure, that you have the haarcascade_frontalface_default.xml file in your folder, this can be found in the OpenCV installation folder
 #include <opencv2/opencv.hpp>
  #include <opencv2/imgproc/imgproc.hpp>
 #include <vector>
 #include <string>
using namespace cv;

CascadeClassifier face;

int main()
{
    VideoCapture vid(0);
 Size s(vid.get(CV_CAP_PROP_FRAME_WIDTH),vid.get(CV_CAP_PROP_FRAME_HEIGHT));
 double fps=vid.get(CV_CAP_PROP_FPS);
//  namedWindow("window");
    namedWindow("original");
    //createTrackbar("Track1","window",&track1,2,NULL);
    //createTrackbar("Track2","window",&track2,5,NULL);
    //createTrackbar("Track3","window",&track3,12,NULL);
    Mat image;
    int kernelSize=3;
    Mat prev;
    face.load("haarcascade_frontalface_default.xml");

    while(1)
    {
        vid >> image;
        image.copyTo(prev);
        cvtColor(image,image,CV_BGR2GRAY);
        std::vector<Rect> vec;
        GaussianBlur(image,image,Size(7,7),0,0);
        face.detectMultiScale(image,vec,1.3, 2, 0|CV_HAAR_SCALE_IMAGE, Size(100, 100) );
        for(int i=0;i<vec.size();i++)
        {
            rectangle(prev,vec[i],Scalar(0,0,255));
        }

        imshow("original",prev);
        if(waitKey(30)==27) break;
    }
}