从视频中抓拍图片

#include "opencv2/highgui/highgui.hpp"

#include <opencv2/objdetect/objdetect.hpp>

#include <opencv2/imgproc/imgproc.hpp>

#include <iostream>

#include <vector>

#include <stdio.h>

using namespace cv;

using namespace std;

int process(VideoCapture& capture)

{

int n = 0;

char filename[200];

string window_name = "video | q or esc to quit";
//窗口名称

cout << " \n\t按下【Space】空格键可以截图，图片将存放在工程目录下。\n\n\t【Esc】和【q】键 - 退出程序。 " << endl;

namedWindow(window_name, CV_WINDOW_KEEPRATIO); // CV_WINDOW_KEEPRATIO：保持图像的比例

Mat frame;

for (;;)

{

capture >> frame;

if (frame.empty())

break;

Mat gray;

cvtColor(frame,gray,COLOR_RGB2GRAY);
//彩色转化为灰度图

vector<string> codes;

Mat corners;

findDataMatrix(gray, codes, corners);

drawDataMatrixCodes(frame, codes, corners);

imshow(window_name, frame);

char key = (char) waitKey(1); //delay N millis, usually long enough to display and capture input

switch (key)

{

case 'q':

case 'Q':

case 27: //escape key

return 0;

case ' ': //Save an image

sprintf(filename, "视频截图%.3d.jpg", n++);
//格式化字符串

imwrite(filename, frame);
//保存图片

cout << "\n\t>保存了 " << filename <<"文件到工程目录下"<< endl;

break;

default:

break;

}

}

return 0;

}

int main( )

{

//VideoCapture capture("E:\\图片\\bike.avi");
//从本地载入视频

VideoCapture capture(0);//从摄像头载入视频

if (!capture.isOpened())

{

cerr << "Failed to open a video device or video file!\n" << endl;

return 1;

}

return process(capture);

}