C++ Opencv 人脸检测

简单几行代码实现C++ opencv 摄像头人脸识别：

#include "stdafx.h"
#include
#include
#include
#include
using namespace std;
using namespace cv;

//训练文件
string face_cascade_name = "D:\\opencv-2.4.9\\data\\haarcascades\\haarcascade_frontalface_alt.xml";
CascadeClassifier face_cascade;
string window_name = "人脸识别";

void detectAndDisplay( Mat frame );

int main(){
VideoCapture cap;
Mat img;

if(cap.isOpened())
cap.release();
cap.open(0);
while(1)
{
cap>>img;
waitKey(40);
resize(img,img,Size(img.cols/3,img.rows/3));

    if( !img.data ){
        printf("[error] 没有图片\n");
        return -1;
    }


    if( !face_cascade.load( face_cascade_name ) ){ 
        printf("[error] 无法加载级联分类器文件！\n");
        return -1; 
    }

    detectAndDisplay(img);
}
    waitKey(0);    
}


void detectAndDisplay( Mat frame )

{
    std::vector faces;
    Mat frame_gray;
    cvtColor( frame, frame_gray, CV_BGR2GRAY );
imshow("equalizehist----",frame_gray);
    equalizeHist( frame_gray, frame_gray );
imshow("equalizehist",frame_gray);
    face_cascade.detectMultiScale( frame_gray, faces, 1.1, 2, 0|CV_HAAR_SCALE_IMAGE, Size(30, 30) );

    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( frame, center, Size( faces[i].width*0.5, faces[i].height*0.5), 0, 0, 360, Scalar( 255, 0, 255 ), 4, 8, 0 );
    }
    imshow( window_name, frame );
}