Opencv调用摄像头，显示摄像头图像

#include<opencv2\opencv.hpp>

#include<opencv2\core.hpp>

#include<iostream>

#include <cstdio>

#include <string>

#include <sstream>

using namespace cv;

using namespace std;

const char*keys = {
"{help h usage?||print this message}"
"{@video||Video file,if not defined try to use webcamera}"

};

int main(int, char**)

{
Mat frame;
//--- INITIALIZE VIDEOCAPTURE
VideoCapture cap;
// open the default camera using default API
cap.open(0);
// OR advance usage: select any API backend
int deviceID = 0;             // 0 = open default camera
int apiID = cv::CAP_ANY;      // 0 = autodetect default API
 // open selected camera using selected API
cap.open(deviceID + apiID);
// check if we succeeded
if (!cap.isOpened()) {
cerr << "ERROR! Unable to open camera\n";
return -1;
}
//--- GRAB AND WRITE LOOP
cout << "Start grabbing" << endl
<< "Press any key to terminate" << endl;
for (;;)
{
// wait for a new frame from camera and store it into 'frame'
cap.read(frame);
// check if we succeeded
if (frame.empty()) {
cerr << "ERROR! blank frame grabbed\n";
break;
}
// show live and wait for a key with timeout long enough to show images
imshow("Live", frame);
if (waitKey(5) >= 0)
break;
}
// the camera will be deinitialized automatically in VideoCapture destructor
return 0;

}