Example: vision_checkerboard_detectors

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2025, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/gui/CDisplayWindow.h>
#include <mrpt/img/CImage.h>
#include <mrpt/system/CTimeLogger.h>
#include <mrpt/vision/chessboard_find_corners.h>

#include <chrono>
#include <iostream>
#include <thread>

using namespace std;
using namespace mrpt;
using namespace mrpt::img;
using namespace mrpt::system;
using namespace mrpt::gui;

#include <mrpt/examples_config.h>
std::string myDataDir = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_checkerboard_detectors/");

// ------------------------------------------------------
//              TestCheckerboardDetectors
// ------------------------------------------------------
void TestCheckerboardDetectors()
{
  CTimeLogger timlog;

  // Load img:
  CImage img;
  if (!img.loadFromFile(myDataDir + string("test_1_checkerboard_9x6.jpg")))
    throw std::runtime_error("Can't load demo image!");

  // Detect multiple-checkerboards:
  vector<TPixelCoordf> cornerCoords;
  const unsigned int checkerboard_size_x = 6;
  const unsigned int checkerboard_size_y = 9;

  // Detect:
  timlog.enter("findChessboardCorners");

  // bool detectOk1 =
  mrpt::vision::findChessboardCorners(
      img, cornerCoords, checkerboard_size_x, checkerboard_size_y,
      true  // normalize_image
  );

  timlog.leave("findChessboardCorners");

  // Draw:
  CImage img_detect1 = img;
  img_detect1.drawChessboardCorners(cornerCoords, checkerboard_size_x, checkerboard_size_y);

  // Show results:
  CDisplayWindow win1("Detected checkerboard");
  win1.showImage(img_detect1);

  timlog.dumpAllStats();
  timlog.clear();

  // wait till user closes any window:
  while (win1.isOpen())
  {
    std::this_thread::sleep_for(10ms);
  }
}

// ------------------------------------------------------
//                      MAIN
// ------------------------------------------------------
int main()
{
  try
  {
    TestCheckerboardDetectors();
    return 0;
  }
  catch (const std::exception& e)
  {
    std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
    return -1;
  }
}