/*

功能：实现对眼睛、脸部的跟踪。
版本：1.0 
时间：2014-4-27
*/
#include <opencv2/objdetect/objdetect.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/core/core.hpp>

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

using namespace std;
using namespace cv;


void detectEyeAndFace( Mat frame );
//将下面两个文件复制到当前工程下。
//当前文件路径应该是OpenCV安装路径下的sources\data\haarcascades目录下
String face_cascade_name = "haarcascade_frontalface_alt.xml";
String eyes_cascade_name = "haarcascade_eye_tree_eyeglasses.xml";
CascadeClassifier face_cascade;
CascadeClassifier eyes_cascade;

RNG rng(12345);

int main( int argc, const char** argv )
{
	Mat oneFrame;
	/*	Mat test;
	test=imread("a.jpg");
	imshow("",test);
	waitKey(0);    */
	//判断face_cascade_name、eye_cascade_name能够顺利加载
	if( !face_cascade.load( face_cascade_name ) ){ printf("face_cascade_name加载失败\n"); return -1; };
	if( !eyes_cascade.load( eyes_cascade_name ) ){ printf("eye_cascade_name加载失败\n"); return -1; };

	
	 
	VideoCapture vCp("Sample.avi");

	if( vCp.isOpened())	
	{
		while( true )
		{
			
			vCp>>oneFrame;

			//-- 3. Apply the classifier to the frame
			if( !oneFrame.empty() )
			{ detectEyeAndFace( oneFrame ); }
			else
			{ printf(" 当前视频文件为空!"); break; }

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

		}
	}
	return 0;
}


void detectEyeAndFace( Mat oneFrame )
{
	std::vector<Rect> faces;  //脸部标注框
	Mat grayFrame;

	cvtColor( oneFrame, grayFrame, CV_BGR2GRAY );
	equalizeHist( grayFrame, grayFrame );

	face_cascade.detectMultiScale( grayFrame, faces, 1.1, 2, 0|CV_HAAR_SCALE_IMAGE, Size(30, 30) );

	for( size_t i = 0; i < faces.size(); i++ )
	{
		Point center( int(faces[i].x + faces[i].width*0.5), int(faces[i].y + faces[i].height*0.5) );
		ellipse( oneFrame, center, Size( int(faces[i].width*0.5), int(faces[i].height*0.5)), 0, 0, 360, Scalar( 255, 0, 255 ), 2, 8, 0 );

		Mat faceROI = grayFrame( faces[i] );  //得到当前标注的脸部区域
		std::vector<Rect> eyes;//眼睛标注


		eyes_cascade.detectMultiScale( faceROI, eyes, 1.1, 2, 0 |CV_HAAR_SCALE_IMAGE, Size(30, 30) );

		for( size_t j = 0; j < eyes.size(); j++ )
		{
			Point center( int(faces[i].x + eyes[j].x + eyes[j].width*0.5), int(faces[i].y + eyes[j].y + eyes[j].height*0.5) ); 
			int radius = cvRound( (eyes[j].width + eyes[i].height)*0.25 );
			circle( oneFrame, center, radius, Scalar( 255, 0, 0 ), 3, 8, 0 );
		}
	} 

	imshow( "眼镜和脸部跟踪检测", oneFrame );
}

参考文献：

1.迭代的是人，递归的是神》OpenCV学习笔记（二十七）——基于级联分类器的目标检测objdect

http://blog.csdn.net/yang_xian521/article/details/6973667