OpenCV 级联分类器

 #include "opencv2/objdetect/objdetect.hpp"
  #include "opencv2/highgui/highgui.hpp"
  #include "opencv2/imgproc/imgproc.hpp"

  #include <iostream>
  #include <stdio.h>

  using namespace std;
  using namespace cv;

  /** 函数声明 */
  void detectAndDisplay( Mat frame );

  /** 全局变量 */
  string face_cascade_name = "haarcascade_frontalface_alt.xml";
  string eyes_cascade_name = "haarcascade_eye_tree_eyeglasses.xml";
  CascadeClassifier face_cascade;
  CascadeClassifier eyes_cascade;
  string window_name = "Capture - Face detection";
  RNG rng();

  /** @主函数 */
  int main( int argc, const char** argv )
  {
    CvCapture* capture;
    Mat frame;

    //-- 1. 加载级联分类器文件
    if( !face_cascade.load( face_cascade_name ) ){ printf("--(!)Error loading\n"); return -; };
    if( !eyes_cascade.load( eyes_cascade_name ) ){ printf("--(!)Error loading\n"); return -; };

    //-- 2. 打开内置摄像头视频流
    capture = cvCaptureFromCAM( - );
    if( capture )
    {
      while( true )
      {
    frame = cvQueryFrame( capture );

    //-- 3. 对当前帧使用分类器进行检测
        if( !frame.empty() )
        { detectAndDisplay( frame ); }
        else
        { printf(" --(!) No captured frame -- Break!"); break; }

        int c = waitKey();
        if( (char)c == 'c' ) { break; }
       }
    }
    return ;
  }

 /** @函数 detectAndDisplay */
 void detectAndDisplay( Mat frame )
 {
   std::vector<Rect> faces;
   Mat frame_gray;

   cvtColor( frame, frame_gray, CV_BGR2GRAY );
   equalizeHist( frame_gray, frame_gray );

   //-- 多尺寸检测人脸
   face_cascade.detectMultiScale( frame_gray, faces, 1.1, , |CV_HAAR_SCALE_IMAGE, Size(, ) );

   for( int i = ; i < faces.size(); i++ )
   {
     Point center( faces[i].x + faces[i].width*0.5, faces[i].y + faces[i].height*0.5 );
     ellipse( frame, center, Size( faces[i].width*0.5, faces[i].height*0.5), , , , Scalar( , ,  ), , ,  );

     Mat faceROI = frame_gray( faces[i] );
     std::vector<Rect> eyes;

     //-- 在每张人脸上检测双眼
     eyes_cascade.detectMultiScale( faceROI, eyes, 1.1, ,  |CV_HAAR_SCALE_IMAGE, Size(, ) );

     for( int j = ; j < eyes.size(); j++ )
      {
        Point center( faces[i].x + eyes[j].x + eyes[j].width*0.5, faces[i].y + eyes[j].y + eyes[j].height*0.5 );
        int radius = cvRound( (eyes[j].width + eyes[i].height)*0.25 );
        circle( frame, center, radius, Scalar( , ,  ), , ,  );
      }
   }
   //-- 显示结果图像
   imshow( window_name, frame );
  }