detect_calibration_pattern.cpp

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/*
 * Copyright (c) 2011, Willow Garage, Inc.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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#include <turtlebot_arm_kinect_calibration/detect_calibration_pattern.h>

void PatternDetector::setCameraMatrices(cv::Matx33d K_, cv::Mat D_)
{
  K = K_;
  D = D_;
}

void PatternDetector::setPattern(cv::Size grid_size_, float square_size_, Pattern pattern_type_, cv::Point3f offset_)
{
  ideal_points = calcChessboardCorners(grid_size_, square_size_, pattern_type_, offset_);
  pattern_type = pattern_type_;
  grid_size = grid_size_;
  square_size = square_size_;
}

object_pts_t PatternDetector::calcChessboardCorners(cv::Size boardSize, float squareSize, Pattern patternType,
                                                    cv::Point3f offset)
{
  object_pts_t corners;
  switch (patternType)
  {
    case CHESSBOARD:
    case CIRCLES_GRID:
      for (int i = 0; i < boardSize.height; i++)
        for (int j = 0; j < boardSize.width; j++)
          corners.push_back(cv::Point3f(float(j * squareSize), float(i * squareSize), 0) + offset);
      break;
    case ASYMMETRIC_CIRCLES_GRID:
      for (int i = 0; i < boardSize.height; i++)
        for (int j = 0; j < boardSize.width; j++)
          corners.push_back(cv::Point3f(float(i * squareSize), float((2 * j + i % 2) * squareSize), 0) + offset);
      break;
    default:
      std::logic_error("Unknown pattern type.");
  }
  return corners;
}

int PatternDetector::detectPattern(cv::Mat& image_in, Eigen::Vector3f& translation, Eigen::Quaternionf& orientation,
                                   cv::Mat& image_out)
{
  translation.setZero();
  orientation.setIdentity();

  bool found = false;

  observation_pts_t observation_points;

  switch (pattern_type)
  {
    case ASYMMETRIC_CIRCLES_GRID:
      found = cv::findCirclesGrid(image_in, grid_size, observation_points,
                                  cv::CALIB_CB_ASYMMETRIC_GRID | cv::CALIB_CB_CLUSTERING);
      break;
    case CHESSBOARD:
      found = cv::findChessboardCorners(image_in, grid_size, observation_points, cv::CALIB_CB_ADAPTIVE_THRESH);
      break;
    case CIRCLES_GRID:
      found = cv::findCirclesGrid(image_in, grid_size, observation_points, cv::CALIB_CB_SYMMETRIC_GRID);
      break;
  }

  if (found)
  {
    // Do subpixel ONLY IF THE PATTERN IS A CHESSBOARD
    if (pattern_type == CHESSBOARD)
    {
      cv::cornerSubPix(image_in, observation_points, cv::Size(5, 5), cv::Size(-1, -1),
                       cv::TermCriteria(cv::TermCriteria::MAX_ITER + cv::TermCriteria::EPS, 100, 0.01));
    }

    cv::solvePnP(cv::Mat(ideal_points), cv::Mat(observation_points), K, D, rvec, tvec, false);
    cv::Rodrigues(rvec, R); //take the 3x1 rotation representation to a 3x3 rotation matrix.

    cv::drawChessboardCorners(image_out, grid_size, cv::Mat(observation_points), found);

    convertCVtoEigen(tvec, R, translation, orientation);
  }

  return found;
}

void convertCVtoEigen(cv::Mat& tvec, cv::Mat& R, Eigen::Vector3f& translation, Eigen::Quaternionf& orientation)
{
  // This assumes that cv::Mats are stored as doubles. Is there a way to check this?
  // Since it's templated...
  translation = Eigen::Vector3f(tvec.at<double>(0, 0), tvec.at<double>(0, 1), tvec.at<double>(0, 2));

  Eigen::Matrix3f Rmat;
  Rmat << R.at<double>(0, 0), R.at<double>(0, 1), R.at<double>(0, 2),
          R.at<double>(1, 0), R.at<double>(1, 1), R.at<double>(1, 2),
          R.at<double>(2, 0), R.at<double>(2, 1), R.at<double>(2, 2);

  orientation = Eigen::Quaternionf(Rmat);
}