从视频流获取图像

      利用ViSP也可以从输入视频流获取图像。支持格式包括avi，mp4，mov，ogv，flv等常见视频格式。下面创建的这个程序要求安装第三方库OpenCV。

 1 #include <visp/vpDisplayGDI.h>

 2 #include <visp/vpDisplayOpenCV.h>

 3 #include <visp/vpDisplayX.h>

 4 #include <visp/vpTime.h>//允许使用其下的计时函数

 5 #include <visp/vpVideoReader.h>//允许读取视频流

 6 int main(int argc, char** argv)

 7 {

 8 #if defined(VISP_HAVE_OPENCV) && (VISP_HAVE_OPENCV_VERSION >= 0x020100) || defined(VISP_HAVE_FFMPEG)

 9   try {

10     std::string videoname = "video.mpg";

11     for (int i=0; i<argc; i++) {

12       if (std::string(argv[i]) == "--name")

13         videoname = std::string(argv[i+1]);

14       else if (std::string(argv[i]) == "--help") {

15         std::cout << "\nUsage: " << argv[0] << " [--name <video name>] [--help]\n" << std::endl;

16         return 0;

17       }

18     }

19     vpImage<unsigned char> I;

20     vpVideoReader g;//创建一个视频读取对象

21     g.setFileName(videoname);//设置视频的文件名

22     g.open(I);//初始化帧读取工具

23     std::cout << "video name: " << videoname << std::endl;

24     std::cout << "video framerate: " << g.getFramerate() << "Hz" << std::endl;

25     std::cout << "video dimension: " << I.getWidth() << " " << I.getHeight() << std::endl;

26 #ifdef VISP_HAVE_X11

27     vpDisplayX d(I);

28 #elif defined(VISP_HAVE_GDI)

29     vpDisplayGDI d(I);

30 #elif defined(VISP_HAVE_OPENCV)

31     vpDisplayOpenCV d(I);

32 #else

33     std::cout << "No image viewer is available..." << std::endl;

34 #endif

35     vpDisplay::setTitle(I, "Video reader");

36     while (! g.end() ) {

37       double t = vpTime::measureTimeMs();

38       g.acquire(I);

39       vpDisplay::display(I);

40       vpDisplay::flush(I);

41       if (vpDisplay::getClick(I, false)) break;

42       vpTime::wait(t, 1000. / g.getFramerate());

43     }

44   }

45   catch(vpException e) {

46     std::cout << e.getMessage() << std::endl;

47   }

48 #else

49   (void)argc;

50   (void)argv;

51   std::cout << "Install OpenCV or ffmpeg and rebuild ViSP to use this example." << std::endl;

52 #endif

53 }