ashwath1993's profile - activity

Is there a way to return anything other than void from a callback?
I want to return a message from the call back as I want to define the callback as .h so i can call it multiple times for different subscribers.
Is this possible in ros?

void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
ROS_INFO("I heard: [%s]", msg->data.c_str());
}

since i can change the callback in general is a function. But where can I return the value to?

ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback);

Since the callback is called from the subscribe. I have a separate callback for each of those topics, even though they carry the same message (left side carries one type and right the other). Is there a way to use a single callback function to handle both types of messages and handle all the requests at the same time?

nodelet name appended to topic Hi, I created a nodelet to read a point cloud. It is a small example taken from the node

This was sufficient for what I wanted to achieve. Thanks!

Hi,

I have a node that receives camera messages. I want the node to shutdown when the rosbag is done playing. I know I can do this with roslaunch. But I wanted to know if I could do this with code.

I noticed that my code works for some recordings and fails for others.

void callback(const sensor_msgs::ImageConstPtr& msg)
{
if(sub.getNumPublishers() == 0)
{
 // run main algo and write results
 ros::shutdown();
}
else
{
   // process message
}

}

Is there a way to shutdown the node outside the callback? My subscriber is part of a class and the subscriber is initialized with the constructor.

MyClass(ros::NodeHandle& n)
{
  sub = n.subscribe<sensor_msgs::Image>("/camera/image_color", 100, &MyClass::callback, this);
}

My node is defined as follows

int main(int argc, char * argv[])
{
ros::init(argc, argv, "calib_node");

ros::NodeHandle n;
MyClass obj(n);
ros::spin();

return 0;
}

Automatic node shutdown if topic is no longer receiving messages Hi, I have a node that receives camera messages. I wa

Fusing multiple IMU inputs with ROS Hi, I wanted to know if there is a package that already exists that can fuse multi

I am trying to build single c++ file which contains a class that handles both subscribers and publishers. I want to publish multiple instance of a msg (representing different sensors) using the same class.
I wanted to know if such a system is possible on roscpp

#include <ros/ros.h>
class SubscribeAndPublish
{
 public:
SubscribeAndPublish()
{
//Topic you want to publish
pub_ = n_.advertise<ros_work::sensor>("sensors", 1000);
input();
ros::Rate loop_rate(10);
while(ros::ok())
{
pub_.publish(msg); //publishes the msg
ros::spinOnce(); //done to handle callbacks
loop_rate.sleep(); //sleep till the time is done --10
}
}
void input()
{
  int id,t;
  long int mem;
  ROS_INFO("Enter the ID: ");
  scanf("%d", &id);
  ROS_INFO("Enter the memory: ");
  scanf("%ld", &mem);
  msg.id = id;
  msg.memory = mem;
  msg.name = "test";
msg.state = true;
}

private:
ros::NodeHandle n_; 
ros::Publisher pub_;
ros_work::sensor msg;
//ros::Subscriber sub_;

};//End of class SubscribeAndPublish

int main(int argc, char **argv)
{
 //Initiate ROS
 ros::init(argc, argv, "sensors_class");

 //Create an object of class SubscribeAndPublish that will take care of everything
 SubscribeAndPublish SAPObject[4];
 ros::spin();

 return 0;
 }

Cartographer uses TF2. The idea is that now the frame name should follow the new naming convention. i.e frame_id = "odo

Rviz displays the pointcloud data if you subscribe to the topic and in the correct frame. To extract the coordinates of

If you iterate over the pointcloud, you can get all the coordinates. The question needs more clarity.

Have you tried rospack find turtlebot_teleop ? If rospack can't find it, then it must've been deleted if you did a apt-g

I have managed to build a nodelet (tegra_stereo) and it is detected when I run "rospack plugins --attrib=plugin nodelet"

 image_view /home/ashwath/catkin_ws/src/image_pipeline/image_view/nodelet_plugins.xml
 image_proc /home/ashwath/catkin_ws/src/image_pipeline/image_proc/nodelet_plugins.xml
 image_rotate /home/ashwath/catkin_ws/src/image_pipeline/image_rotate/nodelet_plugins.xml
 image_publisher /home/ashwath/catkin_ws/src/image_pipeline/image_publisher/nodelet_plugins.xml
 stereo_image_proc /home/ashwath/catkin_ws/src/image_pipeline/stereo_image_proc/nodelet_plugins.xml
 depth_image_proc /home/ashwath/catkin_ws/src/image_pipeline/depth_image_proc/nodelet_plugins.xml
 tegra_stereo /home/ashwath/catkin_ws/src/tegra_stereo/nodelet_plugins.xml
 pointgrey_camera_driver/home/ashwath/catkin_ws/src/pointgrey_camera_driver/pointgrey_camera_driver/nodelet_plugins.xml

I want to run the nodelet. I couldn't find any helpful tutorial to do that. How do I start the nodelet? Or how to call the nodelet on another ros program?

Update 2 I could launch the nodelet using the following launch file.

<launch>
<node pkg="nodelet" type="nodelet" name="standalone_nodelet"  args="manager"/>
<node pkg="nodelet" type="nodelet" name="tegra" args="load tegra_stereo/tegra_stereo_proc 
standalone_nodelet" output="screen">
 </node>          
</launch>

This is what I get on rqt_graph standalone_nodelet doesn't connect to tegra_stereo

This is on my rostopic list

/clock
/kitti_stereo/left/camera_info 
/kitti_stereo/left/image_rect
/kitti_stereo/right/camera_info
/kitti_stereo/right/image_rect
/rosout
/rosout_agg
/standalone_nodelet/bond
/statistics
/stereo/cam0/image_rect
/stereo/cam0/image_rect/compressed
/stereo/cam0/image_rect/compressed/parameter_descriptions
/stereo/cam0/image_rect/compressed/parameter_updates
/stereo/cam0/image_rect/compressedDepth
/stereo/cam0/image_rect/compressedDepth/parameter_descriptions
/stereo/cam0/image_rect/compressedDepth/parameter_updates
/stereo/cam0/image_rect/theora
/stereo/cam0/image_rect/theora/parameter_descriptions
/stereo/cam0/image_rect/theora/parameter_updates
/stereo/cam1/image_rect
/stereo/cam1/image_rect/compressed
/stereo/cam1/image_rect/compressed/parameter_descriptions

/stereo/cam1/image_rect/compressed/parameter_updates /stereo/cam1/image_rect/compressedDepth /stereo/cam1/image_rect/compressedDepth/parameter_descriptions /stereo/cam1/image_rect/compressedDepth/parameter_updates /stereo/cam1/image_rect/theora /stereo/cam1/image_rect/theora/parameter_descriptions /stereo/cam1/image_rect/theora/parameter_updates /stereo/disparity /stereo/disparity_raw /stereo/disparity_raw/compressed /stereo/disparity_raw/compressed/parameter_descriptions /stereo/disparity_raw/compressed/parameter_updates /stereo/disparity_raw/compressedDepth /stereo/disparity_raw/compressedDepth/parameter_descriptions /stereo/disparity_raw/compressedDepth/parameter_updates /stereo/disparity_raw/theora /stereo/disparity_raw/theora/parameter_descriptions /stereo/disparity_raw/theora/parameter_updates /tf

The nodelet subscribes to the following topics but it does not work for me. There are no messages on the /stereo topics. Any insights on doing this? Thanks!

If the second node doesn't have any data from the first node, what work can it do? In any case, you can place the task

In general, for ICP to work well you will need to have planar regions that can be detected. If you have irregular surfac

You have to do a ground plane detection. There are several approaches using PCL like planar segmentation. Just filteri

Have you tried the velodyne driver? It works perfectly with the VLP 16 series. A screenshot of the problem can be more

The tutorials on the ROS website are a great way to start. Once you complete that, you can do the husky demo as suggeste

Both words can be used interchangeably in general. Ego-motion is defined as the 3D motion of a system (ex camera) with

ROS logging uses approach 1. All log messages are passed to /rosout. The first approach is simple to implement as well

Thanks a lot! I didn't know of this parameter.

Hi,

I want to shutdown all nodes from within a ros node. ros::shutdown() kills the current node but does not kill the other nodes.

I know that all nodes can be killed using the terminal and through the launch file. But I test if a certain condition is met and only in such a circumstance I want all the nodes to shutdown.

Thanks!

Hi, the rosnode.kill_nodes and the API is for the python variant. I am not able to find the C++ equivalent.

shutdown alll nodes Hi, I want to shutdown all nodes from within a ros node. ros::shutdown() kills the current node but

I have a ros package which builds a image_proc like node for cuda SGM.
I have built the package and the nodelet is built. I am not sure how to run it. I have looked through the ros tutorials but there isn't a clear explanation of how to run a nodelet for a generic case.

The nodelet is exported as follows

#include <pluginlib/class_list_macros.h>
PLUGINLIB_EXPORT_CLASS(tegra_stereo::TegraStereoProc, nodelet::Nodelet)

After this, how do call this nodelet? Since I do not have a cpp file like the image_proc or stereo_image_proc to directly call the method. Is there a way to launch the nodelet or how do I launch it?

Thanks!

Where do I call the callAvailable() if I have the nodehandle in a class?