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Definition of a ROI publisher with c++

asked 2013-04-22 22:36:28 -0500

Bison gravatar image

updated 2013-04-24 00:25:45 -0500

Philip gravatar image

Hi communitiy, I'm currently using the procrob functional face detection package, which is completely written in c++. In one of the functions I am getting a rectangle that includes a recognized face. The variables that I get are: x- and y-postition of the upper left corner pixel and the width and height of the rectangle. I want to publish these information as a RegionOfInterest. But I don't know how to define the ROI-Publisher in c++. Does anyone else know?

Thank you for your help, Greetings from Germany, Bison

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answered 2013-04-23 02:56:13 -0500

There is a pretty good tutorial describing how to write topic publishers in C++.

Here is a small code sample that should get you started. Note that you'll need to also set up a package, package.xml, and CMakeLists.txt as described here.

#include "ros/ros.h"
#include "sensor_msgs/RegionOfInterest.h"

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

  ros::Publisher pub = n.advertise<sensor_msgs::RegionOfInterest>("faceROI", 1000);

  ros::Rate loop_rate(10);
  while (ros::ok())
    <do your code to calculate Face ROI here>

    sensor_msgs::RegionOfInterest roi_msg;
    roi_msg.x_offset = 10;
    roi_msg.y_offset = 10;
    roi_msg.height = 200;
    roi_msg.width = 100;


  return 0;
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Thank you very much. That's exactly what i was looking for. I did the tutorial but I am really not into c++ yet. Greetings from Germany

Bison gravatar image Bison  ( 2013-04-23 03:10:38 -0500 )edit

answered 2013-04-22 22:54:15 -0500

dornhege gravatar image

You mean this message?

That looks to have exactly the values that you are getting, so you can just put them in there.

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Yes, that's exactly the type of message I want to publish. My problem is that I'm not very familiar with c++. I just don't know how to write the publisher for that type of message.

Bison gravatar image Bison  ( 2013-04-23 01:05:23 -0500 )edit

Ah, there's the problem. If @Jeremy Zoss's answer fixes your problem click the checkmark to accept it.

dornhege gravatar image dornhege  ( 2013-04-23 07:35:15 -0500 )edit

Done. Thank you for your answers.

Bison gravatar image Bison  ( 2013-04-23 19:43:57 -0500 )edit

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Asked: 2013-04-22 22:36:28 -0500

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Last updated: Apr 23 '13