barcode_reader_nodelet.cpp

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#include "zbar_ros/barcode_reader_nodelet.h"
#include "pluginlib/class_list_macros.h"
#include "std_msgs/String.h"

namespace zbar_ros
{

  BarcodeReaderNodelet::BarcodeReaderNodelet()
  {
    scanner_.set_config(zbar::ZBAR_NONE, zbar::ZBAR_CFG_ENABLE, 1);
  }

  void BarcodeReaderNodelet::onInit()
  {
    nh_ = getNodeHandle();
    private_nh_ = getPrivateNodeHandle();

    barcode_pub_ = nh_.advertise<std_msgs::String>("barcode", 10,
        boost::bind(&BarcodeReaderNodelet::connectCb, this),
        boost::bind(&BarcodeReaderNodelet::disconnectCb, this));
    
    private_nh_.param<double>("throttle_repeated_barcodes", throttle_, 0.0);
    if (throttle_ > 0.0){
      clean_timer_ = nh_.createTimer(ros::Duration(10.0), boost::bind(&BarcodeReaderNodelet::cleanCb, this));
    }
  };

  void BarcodeReaderNodelet::connectCb()
  {
    if (!camera_sub_ && barcode_pub_.getNumSubscribers() > 0)
    {
      NODELET_INFO("Connecting to camera topic.");
      camera_sub_ = nh_.subscribe("image", 10, &BarcodeReaderNodelet::imageCb, this);
    }
  }

  void BarcodeReaderNodelet::disconnectCb()
  {
    if (barcode_pub_.getNumSubscribers() == 0)
    {
      NODELET_INFO("Unsubscribing from camera topic.");
      camera_sub_.shutdown();
    }
  }

  void BarcodeReaderNodelet::imageCb(const sensor_msgs::ImageConstPtr &image)
  {
    cv_bridge::CvImageConstPtr cv_image;
    cv_image = cv_bridge::toCvShare(image, "mono8");

    zbar::Image zbar_image(cv_image->image.cols, cv_image->image.rows, "Y800", cv_image->image.data,
        cv_image->image.cols * cv_image->image.rows);
    scanner_.scan(zbar_image);

    // iterate over all barcode readings from image
    for (zbar::Image::SymbolIterator symbol = zbar_image.symbol_begin();
         symbol != zbar_image.symbol_end(); ++symbol)
    {
      std::string barcode = symbol->get_data();
      // verify if repeated barcode throttling is enabled
      if (throttle_ > 0.0)
      {
        // check if barcode has been recorded as seen, and skip detection
        if (barcode_memory_.count(barcode) > 0)
        {
          // check if time reached to forget barcode
          if (ros::Time::now() > barcode_memory_.at(barcode))
          {
            NODELET_DEBUG("Memory timed out for barcode, publishing");
            barcode_memory_.erase(barcode);
          }
          else
          {
            // if timeout not reached, skip this reading
            continue;
          }
        }
        // record barcode as seen, with a timeout to 'forget'
        barcode_memory_.insert(std::make_pair(barcode, ros::Time::now() + ros::Duration(throttle_)));
      }

      // publish barcode
      std_msgs::String barcode_string;
      barcode_string.data = barcode;
      barcode_pub_.publish(barcode_string);
    }

    zbar_image.set_data(NULL, 0);
  }

  void BarcodeReaderNodelet::cleanCb()
  {
    for (boost::unordered_map<std::string, ros::Time>::iterator it = barcode_memory_.begin();
         it != barcode_memory_.end(); ++it)
    {
      if (ros::Time::now() > it->second)
      {
        NODELET_DEBUG_STREAM("Cleaned " << it->first << " from memory");
        barcode_memory_.erase(it);
      }
    }

  }
}  // namespace zbar_ros

PLUGINLIB_EXPORT_CLASS(zbar_ros::BarcodeReaderNodelet, nodelet::Nodelet);