haar_test.cpp

#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
 
#include <iostream>
#include <cstdio>
 
using namespace std;
using namespace cv;
 
int main(int argc, char ** argv)
{
    Mat image;

    if (argc < 2) {
        cerr << "No image provided." << endl;
        return -1;
    }

    image = imread(argv[1], CV_LOAD_IMAGE_COLOR);  
    namedWindow("window1", 1);   
    imshow("window1", image);
 
    // Load Face cascade (.xml file)
    CascadeClassifier face_cascade;
    face_cascade.load("./haarcascade_frontalface_alt2.xml");
 
    // Detect faces
    std::vector<Rect> faces;
    face_cascade.detectMultiScale(image, faces, 1.1, 2, 0|CV_HAAR_SCALE_IMAGE, Size(30, 30));
 
    // Draw circles on the detected faces
    for(int i = 0; i < faces.size(); i++)
    {
        Point center(faces[i].x + faces[i].width * 0.5, faces[i].y + faces[i].height * 0.5);
        ellipse(image, center, Size(faces[i].width * 0.5, faces[i].height * 0.5), 0, 0, 360, Scalar(255, 0, 255), 4, 8, 0);
    }
     
    imshow("Detected Face", image);
     
    waitKey(0);                   
    return 0;
}