ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question

Revision history [back]

click to hide/show revision 1
initial version

answered 2022-09-26 10:18:05 -0600

Janebek gravatar image

I firgured it out!

Put the below code into class member.

typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol; message_filters::Synchronizer<sync_pol> *sync;

And then in the ClientHandler::ClientHandler function put those two lines.

sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub); sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));

Now it can receive two topics at the same time!

Hope this will help you guys with the same problem!

I firgured it out!

Put the below code into class member.

 typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
message_filters::Synchronizer<sync_pol> *sync;

And then in the ClientHandler::ClientHandler function put those two lines.

 sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);
sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));

For a more general view, based on @ravijoshi 's code, I modified it to two topics.

#include <ros/ros.h>
#include <message_filters/subscriber.h>
#include <sensor_msgs/Image.h>

using namespace sensor_msgs;
using namespace message_filters;

class ClientHandler
{
public:
  ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_sub);
  void CamImgCb(const ImageConstPtr& image);

private:
  ros::NodeHandle n;
  std::string topic_rgb,topic_depth;

  //add members in two topics situation
  message_filters::Subscriber<Image> rgb_sub;
  message_filters::Subscriber<Image> depth_sub;
  typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
  message_filters::Synchronizer<sync_pol> *sync;
};

ClientHandler::ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_depth) : n(nh), topic_rgb(topic_name_rgb),topic_depth(topic_name_depth)
{
  // the following declaration does not work. hence it is commented.
  // the subscriber is in a local scope
  // message_filters::Subscriber<Image> rgb_sub(n, topic, 1);

  // let's make them a class member and then call subscribe as shown below
  rgb_sub.subscribe(n, topic_rgb, 1);
  depth_sub.subscribe(n,topic_depth,1);

  // here is for the synchronizer
   sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);

  // now bind a callback
   sync->registerCallback(boost::bind(&ClientHandler::CamImgCb,this,_1,_2));
}

void ClientHandler::CamImgCb(const ImageConstPtr& image_rgb , const ImageConstPtr& image_depth)
{
  ROS_INFO("Sequence: [%d] [%d]", image_rgb->header.seq, imgage_depth->header.seq);
}

int main(int argc, char** argv)
{
  ros::init(argc, argv, "image_listener");
  ros::NodeHandle n;

  std::string topic_rgb = "/usb_cam/image_raw";
  std::string topic_depth = "/usb_cam/camera_info";
  ClientHandler ClientHandler(n, topic_rgb,topic_depth);

  ros::spin();
  return 0;
}

Now it can receive two topics at the same time!

Hope this will help you guys with the same problem!

I firgured it out!

Put the below code into class member.

typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
message_filters::Synchronizer<sync_pol> *sync;

And then in the ClientHandler::ClientHandler function put those two lines.

sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);
sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));

For a more general view, based on @ravijoshi 's code, I modified it to two topics.

#include <ros/ros.h>
#include <message_filters/subscriber.h>
#include <sensor_msgs/Image.h>

using namespace sensor_msgs;
using namespace message_filters;

class ClientHandler
{
public:
  ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_sub);
  void CamImgCb(const ImageConstPtr& image);

private:
  ros::NodeHandle n;
  std::string topic_rgb,topic_depth;

  //add members in two topics situation
  message_filters::Subscriber<Image> rgb_sub;
  message_filters::Subscriber<Image> depth_sub;
  typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
  message_filters::Synchronizer<sync_pol> *sync;
};

ClientHandler::ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_depth) : n(nh), topic_rgb(topic_name_rgb),topic_depth(topic_name_depth)
{
  // the following declaration does not work. hence it is commented.
  // the subscriber is in a local scope
  // message_filters::Subscriber<Image> rgb_sub(n, topic, 1);

  // let's make them a class member and then call subscribe as shown below
  rgb_sub.subscribe(n, topic_rgb, 1);
  depth_sub.subscribe(n,topic_depth,1);

  // here is for the synchronizer
   sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);

  // now bind a callback
   sync->registerCallback(boost::bind(&ClientHandler::CamImgCb,this,_1,_2));
sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));
}

void ClientHandler::CamImgCb(const ClientHandler::GrabRGBD(const ImageConstPtr& image_rgb , const ImageConstPtr& image_depth)
{
  ROS_INFO("Sequence: [%d] [%d]", image_rgb->header.seq, imgage_depth->header.seq);
}

int main(int argc, char** argv)
{
  ros::init(argc, argv, "image_listener");
  ros::NodeHandle n;

  std::string topic_rgb = "/usb_cam/image_raw";
  std::string topic_depth = "/usb_cam/camera_info";
  ClientHandler ClientHandler(n, topic_rgb,topic_depth);

  ros::spin();
  return 0;
}

Now it can receive two topics at the same time!

Hope this will help you guys with the same problem!

I firgured it out!

Put the below code into class member.

typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
message_filters::Synchronizer<sync_pol> *sync;

And then in the ClientHandler::ClientHandler function put those two lines.

sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);
sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));

For a more general view, based on @ravijoshi 's code, I modified it to into two topics.

#include <ros/ros.h>
#include <message_filters/subscriber.h>
#include <sensor_msgs/Image.h>

using namespace sensor_msgs;
using namespace message_filters;

class ClientHandler
{
public:
  ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_sub);
  void CamImgCb(const ImageConstPtr& image);

private:
  ros::NodeHandle n;
  std::string topic_rgb,topic_depth;

  //add members in two topics situation
  message_filters::Subscriber<Image> rgb_sub;
  message_filters::Subscriber<Image> depth_sub;
  typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
  message_filters::Synchronizer<sync_pol> *sync;
};

ClientHandler::ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_depth) : n(nh), topic_rgb(topic_name_rgb),topic_depth(topic_name_depth)
{
  // the following declaration does not work. hence it is commented.
  // the subscriber is in a local scope
  // message_filters::Subscriber<Image> rgb_sub(n, topic, 1);

  // let's make them a class member and then call subscribe as shown below
  rgb_sub.subscribe(n, topic_rgb, 1);
  depth_sub.subscribe(n,topic_depth,1);

  // here is for the synchronizer
   sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);

  // now bind a callback
   sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));
}

void ClientHandler::GrabRGBD(const ImageConstPtr& image_rgb , const ImageConstPtr& image_depth)
{
  ROS_INFO("Sequence: [%d] [%d]", image_rgb->header.seq, imgage_depth->header.seq);
}

int main(int argc, char** argv)
{
  ros::init(argc, argv, "image_listener");
  ros::NodeHandle n;

  std::string topic_rgb = "/usb_cam/image_raw";
  std::string topic_depth = "/usb_cam/camera_info";
  ClientHandler ClientHandler(n, topic_rgb,topic_depth);

  ros::spin();
  return 0;
}

Now it can receive two topics at the same time!

Hope this will help you guys with the same problem!

I firgured it out!

Put the below code into class member.

typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
message_filters::Synchronizer<sync_pol> *sync;

And then in the ClientHandler::ClientHandler function put those two lines.

sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);
sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));

For a more general view, based on @ravijoshi 's code, I modified it into two topics.

#include <ros/ros.h>
#include <message_filters/subscriber.h>
#include <sensor_msgs/Image.h>

using namespace sensor_msgs;
using namespace message_filters;

class ClientHandler
{
public:
  ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_sub);
  void CamImgCb(const GrabRGBD(const ImageConstPtr& image);
image_rgb,const ImageConstPtr& image_depth);

private:
  ros::NodeHandle n;
  std::string topic_rgb,topic_depth;

  //add members in two topics situation
  message_filters::Subscriber<Image> rgb_sub;
  message_filters::Subscriber<Image> depth_sub;
  typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
  message_filters::Synchronizer<sync_pol> *sync;
};

ClientHandler::ClientHandler(ros::NodeHandle& nh, std::string& topic_name_rgb,std::string& topic_name_depth) : n(nh), topic_rgb(topic_name_rgb),topic_depth(topic_name_depth)
{
  // the following declaration does not work. hence it is commented.
  // the subscriber is in a local scope
  // message_filters::Subscriber<Image> rgb_sub(n, topic, 1);

  // let's make them a class member and then call subscribe as shown below
  rgb_sub.subscribe(n, topic_rgb, 1);
  depth_sub.subscribe(n,topic_depth,1);

  // here is for the synchronizer
   sync = new message_filters::Synchronizer<sync_pol>(sync_pol(10), rgb_sub,depth_sub);

  // now bind a callback
   sync->registerCallback(boost::bind(&ClientHandler::GrabRGBD,this,_1,_2));
}

void ClientHandler::GrabRGBD(const ImageConstPtr& image_rgb , const ImageConstPtr& image_depth)
{
  ROS_INFO("Sequence: [%d] [%d]", image_rgb->header.seq, imgage_depth->header.seq);
}

int main(int argc, char** argv)
{
  ros::init(argc, argv, "image_listener");
  ros::NodeHandle n;

  std::string topic_rgb = "/usb_cam/image_raw";
  std::string topic_depth = "/usb_cam/camera_info";
  ClientHandler ClientHandler(n, topic_rgb,topic_depth);

  ros::spin();
  return 0;
}

Now it can receive two topics at the same time!

Hope this will help you guys with the same problem!

ROS Answers is licensed under Creative Commons Attribution 3.0 Content on this site is licensed under a Creative Commons Attribution Share Alike 3.0 license.
about | faq | help | privacy policy | terms of service
Powered by Askbot version 0.10.2