opencv ，打开摄像头

// videocap.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include <stdio.h>
#include <iostream>
#include "opencv2/core/core.hpp"
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"

#ifdef _DEBUG
#pragma comment(lib, "lib/opencv_core2411d")
#pragma comment(lib,"lib/opencv_highgui2411d")
#pragma comment(lib, "lib/opencv_imgproc2411d")

#else
#pragma comment(lib, "lib/opencv_core2411")
#pragma comment(lib, "lib/opencv_highgui2411")
#pragma comment(lib, "lib/opencv_imgproc2411")
#endif

using namespace cv;
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
{
//VideoCapture capture("Video 1.mp4");//读入视频文件
VideoCapture capture(0);//从摄像头读入图像
VideoCapture capture1(1);//从摄像头读入图像
VideoCapture capture2(2);//从摄像头读入图像
//waitKey(4000);
double width = capture.get(CV_CAP_PROP_FRAME_WIDTH);
double height = capture.get(CV_CAP_PROP_FRAME_HEIGHT);
/*capture.set(CV_CAP_PROP_FRAME_WIDTH, 1920);
capture.set(CV_CAP_PROP_FRAME_HEIGHT, 1080);
capture1.set(CV_CAP_PROP_FRAME_WIDTH, 1920);
capture1.set(CV_CAP_PROP_FRAME_HEIGHT, 1080);*/
//if (!capture.isOpened())//函数用来检验是否打开成功
//{
//	cout << "fail to open!" << endl;
//	return -1;
//}
while (1)
{
Mat frame,frame1,frame2;
if (capture.isOpened())
{
//double t1 = (double)getTickCount();
capture >> frame;
//t1 = ((double)getTickCount() - t1) / getTickFrequency();
//imwrite("图片\\" + to_string(i) + ".jpg", frame);
namedWindow("0");
imshow("0", frame);
}
if (capture1.isOpened())
{
capture1 >> frame1;
namedWindow("1", 1);
imshow("1", frame1);
}
if (capture2.isOpened())
{
capture2 >> frame2;
namedWindow("2", 1);
imshow("2", frame2);
}
waitKey(33);
}
//system("pause");
return 0;