discrete_fourier_transform_nodelet.cpp

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// https://github.com/opencv/opencv/blob/2.4/samples/cpp/tutorial_code/core/discrete_fourier_transform/discrete_fourier_transform.cpp
#include <image_transport/image_transport.h>
#include <sensor_msgs/image_encodings.h>
#include <cv_bridge/cv_bridge.h>
#include "opencv2/core/core.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"

#include "opencv_apps/nodelet.h"
#include "opencv_apps/DiscreteFourierTransformConfig.h"

#include <dynamic_reconfigure/server.h>

namespace opencv_apps
{
class DiscreteFourierTransformNodelet : public opencv_apps::Nodelet
{
  image_transport::Publisher img_pub_;
  image_transport::Subscriber img_sub_;
  image_transport::CameraSubscriber cam_sub_;

  boost::shared_ptr<image_transport::ImageTransport> it_;

  typedef opencv_apps::DiscreteFourierTransformConfig Config;
  typedef dynamic_reconfigure::Server<Config> ReconfigureServer;
  Config config_;
  boost::shared_ptr<ReconfigureServer> reconfigure_server_;

  int queue_size_;
  bool debug_view_;
  ros::Time prev_stamp_;

  boost::mutex mutex_;

  std::string window_name_;

  void imageCallbackWithInfo(const sensor_msgs::ImageConstPtr& msg, const sensor_msgs::CameraInfoConstPtr& cam_info)
  {
    doWork(msg, cam_info->header.frame_id);
  }

  void imageCallback(const sensor_msgs::ImageConstPtr& msg)
  {
    doWork(msg, msg->header.frame_id);
  }

  void subscribe()  // NOLINT(modernize-use-override)
  {
    NODELET_DEBUG("Subscribing to image topic.");
    if (config_.use_camera_info)
      cam_sub_ =
          it_->subscribeCamera("image", queue_size_, &DiscreteFourierTransformNodelet::imageCallbackWithInfo, this);
    else
      img_sub_ = it_->subscribe("image", queue_size_, &DiscreteFourierTransformNodelet::imageCallback, this);
  }

  void unsubscribe()  // NOLINT(modernize-use-override)
  {
    NODELET_DEBUG("Unsubscribing from image topic.");
    img_sub_.shutdown();
    cam_sub_.shutdown();
  }

  void reconfigureCallback(Config& config, uint32_t level)
  {
    boost::mutex::scoped_lock lock(mutex_);
    config_ = config;
  }

  void doWork(const sensor_msgs::Image::ConstPtr& image_msg, const std::string& input_frame_from_msg)
  {
    // Work on the image.
    try
    {
      cv::Mat src_image = cv_bridge::toCvShare(image_msg, image_msg->encoding)->image;
      if (src_image.channels() > 1)
      {
        cv::cvtColor(src_image, src_image, CV_BGR2GRAY);
      }

      cv::Mat padded;  // expand input image to optimal size
      int m = cv::getOptimalDFTSize(src_image.rows);
      int n = cv::getOptimalDFTSize(src_image.cols);  // on the border add zero values
      cv::copyMakeBorder(src_image, padded, 0, m - src_image.rows, 0, n - src_image.cols, cv::BORDER_CONSTANT,
                         cv::Scalar::all(0));

      cv::Mat planes[] = { cv::Mat_<float>(padded), cv::Mat::zeros(padded.size(), CV_32F) };
      cv::Mat complex_image;
      cv::merge(planes, 2, complex_image);    // Add to the expanded another plane with zeros
      cv::dft(complex_image, complex_image);  // this way the result may fit in the source matrix

      // compute the magnitude and switch to logarithmic scale
      // => log(1 + sqrt(Re(DFT(I))^2 + Im(DFT(I))^2))
      cv::split(complex_image, planes);                // planes[0] = Re(DFT(I), planes[1] = Im(DFT(I))
      cv::magnitude(planes[0], planes[1], planes[0]);  // planes[0] = magnitude
      cv::Mat magnitude_image = planes[0];
      magnitude_image += cv::Scalar::all(1);  // switch to logarithmic scale
      cv::log(magnitude_image, magnitude_image);

      // crop the spectrum, if it has an odd number of rows or columns
      magnitude_image = magnitude_image(cv::Rect(0, 0, magnitude_image.cols & -2, magnitude_image.rows & -2));
      // rearrange the quadrants of Fourier imagev  so that the origin is at the image center
      int cx = magnitude_image.cols / 2;
      int cy = magnitude_image.rows / 2;

      cv::Mat q0(magnitude_image, cv::Rect(0, 0, cx, cy));    // Top-Left - Create a ROI per quadrant
      cv::Mat q1(magnitude_image, cv::Rect(cx, 0, cx, cy));   // Top-Right
      cv::Mat q2(magnitude_image, cv::Rect(0, cy, cx, cy));   // Bottom-Left
      cv::Mat q3(magnitude_image, cv::Rect(cx, cy, cx, cy));  // Bottom-Right

      cv::Mat tmp;  // swap quadrants (Top-Left with Bottom-Right)
      q0.copyTo(tmp);
      q3.copyTo(q0);
      tmp.copyTo(q3);

      q1.copyTo(tmp);  // swap quadrant (Top-Right with Bottom-Left)
      q2.copyTo(q1);
      tmp.copyTo(q2);
      cv::normalize(magnitude_image, magnitude_image, 0, 255, cv::NORM_MINMAX);

      cv::Mat result_image = cv::Mat::zeros(magnitude_image.rows, magnitude_image.cols, CV_8UC1);
      for (int i = 0; i < magnitude_image.rows; ++i)
      {
        unsigned char* result_data = result_image.ptr<unsigned char>(i);
        float* magnitude_data = magnitude_image.ptr<float>(i);
        for (int j = 0; j < magnitude_image.cols; ++j)
        {
          *result_data++ = (unsigned char)(*magnitude_data++);
        }
      }

      if (debug_view_)
      {
        cv::imshow(window_name_, result_image);
        int c = cv::waitKey(1);
      }
      img_pub_.publish(
          cv_bridge::CvImage(image_msg->header, sensor_msgs::image_encodings::MONO8, result_image).toImageMsg());
    }
    catch (cv::Exception& e)
    {
      NODELET_ERROR("Image processing error: %s %s %s %i", e.err.c_str(), e.func.c_str(), e.file.c_str(), e.line);
    }

    prev_stamp_ = image_msg->header.stamp;
  }

public:
  virtual void onInit()  // NOLINT(modernize-use-override)
  {
    Nodelet::onInit();
    it_ = boost::shared_ptr<image_transport::ImageTransport>(new image_transport::ImageTransport(*nh_));
    pnh_->param("queue_size", queue_size_, 1);
    pnh_->param("debug_view", debug_view_, false);

    if (debug_view_)
    {
      always_subscribe_ = true;
    }
    prev_stamp_ = ros::Time(0, 0);

    window_name_ = "Discrete Fourier Transform Demo";

    reconfigure_server_ = boost::make_shared<dynamic_reconfigure::Server<Config> >(*pnh_);
    dynamic_reconfigure::Server<Config>::CallbackType f =
        boost::bind(&DiscreteFourierTransformNodelet::reconfigureCallback, this, _1, _2);
    reconfigure_server_->setCallback(f);

    img_pub_ = advertiseImage(*pnh_, "image", 1);
    onInitPostProcess();
  }
};
}  // namespace opencv_apps

namespace discrete_fourier_transform
{
class DiscreteFourierTransformNodelet : public opencv_apps::DiscreteFourierTransformNodelet
{
public:
  virtual void onInit()  // NOLINT(modernize-use-override)
  {
    ROS_WARN("DeprecationWarning: Nodelet discrete_fourier_transform/discrete_fourier_transform is deprecated, "
             "and renamed to opencv_apps/discrete_fourier_transform.");
    opencv_apps::DiscreteFourierTransformNodelet::onInit();
  }
};
}  // namespace discrete_fourier_transform

#include <pluginlib/class_list_macros.h>
PLUGINLIB_EXPORT_CLASS(opencv_apps::DiscreteFourierTransformNodelet, nodelet::Nodelet);
PLUGINLIB_EXPORT_CLASS(discrete_fourier_transform::DiscreteFourierTransformNodelet, nodelet::Nodelet);