关于官方教程代码objectdetection里的脸部识别源代码，在毛星云的<>第二章中学习的。但只是镜头闪了一下.

按照原来的代码 并且将需要的文件放在源文件目录后运行程序，镜头闪了一下后，就这样，然后将capture。open（-1），-1改成0后就生成。版本是：vs2015，opencv3.2.0
文件中的代码如下：
/**
* @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.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/highgui.hpp"
#include "opencv2/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 = "lbpcascade_frontalface.xml";
String eyes_cascade_name = "haarcascade_eye_tree_eyeglasses.xml";
CascadeClassifier face_cascade;
CascadeClassifier eyes_cascade;
String window_name = "Capture - Face detection";
/**
* @function main
*/
int main(void)
{
VideoCapture capture;
Mat frame;

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

//-- 2. Read the video stream
capture.open(0);
if (!capture.isOpened()) { printf("--(!)Error opening video capture\n"); return -1; }

while (capture.read(frame))
{
if (frame.empty())
{
printf(" --(!) No captured frame -- Break!");
break;
}

//-- 3. Apply the classifier to the frame
detectAndDisplay(frame);

//-- bail out if escape was pressed
int c = waitKey(10);
if ((char)c == 27) { 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 | CASCADE_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);
}