OPENCV人臉檢測例子

/**
 * @file objectDetection2.cpp
 * @author A. Huaman ( based in the classic facedetect.cpp in samples/c )
 * @brief A simplified version of facedetect.cpp, show how to load a cascade classifier and how to find objects (Face + eyes) in a video stream - Using LBP here
 */
#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;


/** Function Headers */
void detectAndDisplay( Mat frame );


/** Global variables */
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(12345);


/**
 * @function main
 */
int main( void )
{
  VideoCapture capture;
  Mat frame;


  //-- 1. Load the cascade
  if( !face_cascade.load( face_cascade_name ) ){ 
 printf("--(!)Error loading\n"); 
 return -1; 
  };
  if( !eyes_cascade.load( eyes_cascade_name ) ){ 
 printf("--(!)Error loading\n"); 
 return -1;
  };


  //-- 2. Read the video stream
  capture.open(0 );
  if( capture.isOpened() )
  {
    for(;;)
    {
      capture >> frame;


      //-- 3. Apply the classifier to the frame
      if( !frame.empty() )
       { detectAndDisplay( frame ); }
      else
       { printf(" --(!) No captured frame -- Break!"); break; }


      int c = waitKey(10);
      if( (char)c == 'c' ) { break; }


    }
  }
  return 0;
}


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


   cvtColor( frame, frame_gray, COLOR_BGR2GRAY );
   equalizeHist( frame_gray, frame_gray );


   //-- Detect faces
   face_cascade.detectMultiScale( frame_gray, faces, 1.1, 2, 0, Size(80, 80) );


   for( size_t i = 0; i < faces.size(); i++ )
    {
      Mat faceROI = frame_gray( faces[i] );
      std::vector<Rect> eyes;


      //-- In each face, detect eyes
      eyes_cascade.detectMultiScale( faceROI, eyes, 1.1, 2, 0 |CV_HAAR_SCALE_IMAGE, Size(30, 30) );
      if( eyes.size() == 2)
      {
         //-- Draw the face
         Point center( faces[i].x + faces[i].width/2, faces[i].y + faces[i].height/2 );
         ellipse( frame, center, Size( faces[i].width/2, faces[i].height/2), 0, 0, 360, Scalar( 255, 0, 0 ), 2, 8, 0 );


         for( size_t j = 0; j < eyes.size(); j++ )
          { //-- Draw the eyes
            Point eye_center( faces[i].x + eyes[j].x + eyes[j].width/2, faces[i].y + eyes[j].y + eyes[j].height/2 );
            int radius = cvRound( (eyes[j].width + eyes[j].height)*0.25 );
            circle( frame, eye_center, radius, Scalar( 255, 0, 255 ), 3, 8, 0 );
          }
       }


    }
   //-- Show what you got
   imshow( window_name, frame );

}

注意：

1、如果用的是release版本的庫，VS編譯和opencv使用的庫要一致，如果是debug就都是debug，是release就都是release，否則會導致級聯文件加載失敗；

2、另外上面的攝像頭打開，capture.open函數在opencv的例子中是-1，本來應該是0纔對，用-1會導致黑屏，不知道原因是什麼；