image_cb_detector.cpp

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#include <ros/console.h>
#include <ros/ros.h>
#include <cv_bridge/cv_bridge.h>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/calib3d/calib3d.hpp>
#include <image_cb_detector/image_cb_detector.h>

using namespace image_cb_detector;
using namespace std;

bool ImageCbDetector::configure(const ConfigGoal& config)
{
  config_ = config;
  return true;
}

bool ImageCbDetector::detect(const sensor_msgs::ImageConstPtr& ros_image,
                             calibration_msgs::CalibrationPattern& result)
{
  cv::Mat image;
  try
  {
    image = cv_bridge::toCvShare(ros_image, "mono8")->image;
  }
  catch (cv_bridge::Exception error)
  {
    ROS_ERROR("error");
    return false;
  }

  // \todo This code has been pretty much copied from laser_cb_detector. (Wow... this is poor software design)

  // ***** Resize the image based on scaling parameters in config *****
  const int scaled_width  = (int) (.5 + image.cols  * config_.width_scaling);
  const int scaled_height = (int) (.5 + image.rows * config_.height_scaling);
  cv::Mat image_scaled;
  cv::resize(image, image_scaled, cv::Size(scaled_width, scaled_height), 0, 0, CV_INTER_LINEAR);

  // ***** Allocate vector for found corners *****
  vector<cv::Point2f> cv_corners;
  cv_corners.resize(config_.num_x*config_.num_y);

  // ***** Do the actual checkerboard extraction *****
  cv::Size board_size(config_.num_x, config_.num_y);
  int found = cv::findChessboardCorners( image_scaled, board_size, cv_corners, CV_CALIB_CB_ADAPTIVE_THRESH) ;

  if(found)
  {
    ROS_DEBUG("Found CB");
    //ROS_INFO("Found checkerboard. Subpixel window: %i", config_.subpixel_window);


    cv::Size subpixel_window(config_.subpixel_window,
                                       config_.subpixel_window);
    cv::Size subpixel_zero_zone(config_.subpixel_zero_zone,
                                       config_.subpixel_zero_zone);

    // Subpixel fine-tuning stuff
    cv::cornerSubPix( image_scaled, cv_corners, 
                       subpixel_window,
                       subpixel_zero_zone,
                       cv::TermCriteria(CV_TERMCRIT_ITER,20,1e-2));
  }
  else
    ROS_DEBUG("Didn't find CB");

  // ***** Downscale the detected corners and generate the CalibrationPattern message *****
  result.header.stamp    = ros_image->header.stamp;
  result.header.frame_id = ros_image->header.frame_id;

  result.object_points.resize(config_.num_x * config_.num_y);
  for (unsigned int i=0; i < config_.num_y; i++)
  {
    for (unsigned int j=0; j < config_.num_x; j++)
    {
      result.object_points[i*config_.num_x + j].x = j*config_.spacing_x;
      result.object_points[i*config_.num_x + j].y = i*config_.spacing_y;
      result.object_points[i*config_.num_x + j].z = 0.0;
    }
  }

  result.image_points.resize(cv_corners.size());

  for (size_t i=0; i < cv_corners.size(); i++)
  {
    result.image_points[i].x = cv_corners[i].x / config_.width_scaling;
    result.image_points[i].y = cv_corners[i].y / config_.height_scaling;
  }

  result.success = found;

  return true;
}