grabOpenCV.cpp

Example of framegrabbing using OpenCV cv::VideoCapture class.

/****************************************************************************
 *
 * ViSP, open source Visual Servoing Platform software.
 * Copyright (C) 2005 - 2019 by Inria. All rights reserved.
 *
 * This software is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 * See the file LICENSE.txt at the root directory of this source
 * distribution for additional information about the GNU GPL.
 *
 * For using ViSP with software that can not be combined with the GNU
 * GPL, please contact Inria about acquiring a ViSP Professional
 * Edition License.
 *
 * See http://visp.inria.fr for more information.
 *
 * This software was developed at:
 * Inria Rennes - Bretagne Atlantique
 * Campus Universitaire de Beaulieu
 * 35042 Rennes Cedex
 * France
 *
 * If you have questions regarding the use of this file, please contact
 * Inria at visp@inria.fr
 *
 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 * Description:
 * Acquire images using OpenCV cv::VideoCapture.
 *
 * Authors:
 * Fabien Spindler
 *
 *****************************************************************************/

#include <iostream>

#include <visp3/core/vpConfig.h>

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

#include <visp3/core/vpImage.h>
#include <visp3/core/vpImageConvert.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/sensor/vpOpenCVGrabber.h>

// usage: binary <device name>
// device name: 0 is the default to dial with the first camera,
//              1 to dial with a second camera attached to the computer
int main(int argc, char **argv)
{
  try {
    int device = 0;
    if (argc > 1)
      device = atoi(argv[1]);

    std::cout << "Use device: " << device << std::endl;
    cv::VideoCapture cap(device); // open the default camera
#if (VISP_HAVE_OPENCV_VERSION >= 0x030000)
    cap.set(cv::CAP_PROP_FRAME_WIDTH, 640);
    cap.set(cv::CAP_PROP_FRAME_HEIGHT, 480);
#else
    cap.set(CV_CAP_PROP_FRAME_WIDTH, 640);
    cap.set(CV_CAP_PROP_FRAME_HEIGHT, 480);
#endif
    if (!cap.isOpened()) // check if we succeeded
      return -1;
    cv::Mat frame;
    int i = 0;
    while ((i++ < 100) && !cap.read(frame)) {
    }; // warm up camera by skiping unread frames

    std::cout << "Image size: "
#if (VISP_HAVE_OPENCV_VERSION >= 0x030000)
              << (int)cap.get(cv::CAP_PROP_FRAME_WIDTH) << " " << (int)cap.get(cv::CAP_PROP_FRAME_HEIGHT) << std::endl;
#else
              << (int)cap.get(CV_CAP_PROP_FRAME_WIDTH) << " " << (int)cap.get(CV_CAP_PROP_FRAME_HEIGHT) << std::endl;
#endif

    // vpImage<vpRGBa> I; // for color images
    vpImage<unsigned char> I; // for gray images
    vpImageConvert::convert(frame, I);

    vpDisplayOpenCV d(I);

    for (;;) {
      cap >> frame; // get a new frame from camera

      // Convert the image in ViSP format and display it
      vpImageConvert::convert(frame, I);
      vpDisplay::display(I);
      vpDisplay::flush(I);
      if (vpDisplay::getClick(I, false)) // a click to exit
        break;
    }
    // the camera will be deinitialized automatically in VideoCapture
    // destructor
    return EXIT_SUCCESS;
  } catch (const vpException &e) {
    std::cout << "Catch an exception: " << e << std::endl;
    return EXIT_FAILURE;
  }
}

#else
int main()
{
  std::cout << "You do not have OpenCV functionalities to display images..." << std::endl;
  std::cout << "Tip:" << std::endl;
  std::cout << "- Install OpenCV, configure again ViSP using cmake and build again this example" << std::endl;
  return EXIT_SUCCESS;
}
#endif