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point_cloud_srv.cpp

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#include <ros/ros.h>

// Services
#include "laser_assembler/AssembleScans.h"
#include "pr2_arm_navigation_perception/BuildCloudAngle.h"
#include "pr2_msgs/SetPeriodicCmd.h"

// Messages
#include "sensor_msgs/PointCloud.h"
#include "pr2_msgs/LaserScannerSignal.h"

#include <boost/thread/mutex.hpp>


/***
 * This uses the point_cloud_assembler's build_cloud service call to grab all the scans/clouds between two tilt-laser shutters
 * params
 *  * "~target_frame_id" (string) - This is the frame that the scanned data transformed into.  The
 *                                  output clouds are also published in this frame.
 */

namespace pr2_laser_snapshotter
{

using namespace ros;
using namespace std;

class PointCloudSrv
{
private:
  ros::Time laser_time_;
  boost::mutex laser_mutex_;
  ros::ServiceServer cloud_server_;
  ros::Subscriber sub_;
  ros::NodeHandle nh_;

public:
  PointCloudSrv()
  {
    cloud_server_ = nh_.advertiseService("point_cloud_srv/single_sweep_cloud", &PointCloudSrv::buildSingleSweepCloud, this);
    sub_ = nh_.subscribe("laser_tilt_controller/laser_scanner_signal", 40, &PointCloudSrv::scannerSignalCallback, this);

    laser_time_ = Time().fromSec(0);
  }

  bool buildSingleSweepCloud(pr2_arm_navigation_perception::BuildCloudAngle::Request &req,
                             pr2_arm_navigation_perception::BuildCloudAngle::Response &res)
  {
    // send command to tilt laser scanner
    pr2_msgs::SetPeriodicCmd::Request scan_req;
    pr2_msgs::SetPeriodicCmd::Response scan_res;
    scan_req.command.amplitude  = fabs(req.angle_end - req.angle_begin)/2.0;
    scan_req.command.offset = (req.angle_end + req.angle_begin)/2.0;
    scan_req.command.period = req.duration*2.0;
    scan_req.command.profile = "linear";
    if (!ros::service::call("laser_tilt_controller/set_periodic_cmd", scan_req, scan_res))
      ROS_ERROR("PointCloudSrv: error setting laser scanner periodic command");
    else
      ROS_INFO("PointCloudSrv: commanded tilt laser scanner with period %f, amplitude %f and offset %f",
               scan_req.command.period, scan_req.command.amplitude, scan_req.command.offset);


    // wait for signal from laser to know when scan is finished
    Time begin_time = scan_res.start_time;
    Duration timeout = Duration().fromSec(2.0);
    while (laser_time_ < begin_time){
      boost::mutex::scoped_lock laser_lock(laser_mutex_);
      if (ros::Time::now() > begin_time + Duration().fromSec(req.duration) + timeout){
        ROS_ERROR("PointCloudSrv: Timeout waiting for laser scan to come in");
        return false;
      }
      laser_lock.unlock();
      Duration().fromSec(0.05).sleep();
    }
    Time end_time = laser_time_;
    ROS_INFO("PointCloudSrv: generated point cloud from time %f to %f", begin_time.toSec(), end_time.toSec());

    // get a point cloud from the point cloud assembler
    laser_assembler::AssembleScans::Request assembler_req ;
    laser_assembler::AssembleScans::Response assembler_res ;
    assembler_req.begin = begin_time;
    assembler_req.end   = end_time;
    if (!ros::service::call("laser_scan_assembler/build_cloud", assembler_req, assembler_res))
      ROS_ERROR("PointCloudSrv: error receiving point cloud from point cloud assembler");
    else
      ROS_INFO("PointCloudSrv: received point cloud of size %i from point cloud assembler", assembler_res.cloud.points.size());

    res.cloud = assembler_res.cloud;
    return true;
  }


  void scannerSignalCallback(const pr2_msgs::LaserScannerSignalConstPtr& laser_scanner_signal)
  {
    boost::mutex::scoped_lock laser_lock(laser_mutex_);
    // note time when tilt laser is pointing down
    if (laser_scanner_signal->signal == 1)
    {
      laser_time_ = laser_scanner_signal->header.stamp;
    }
  }
} ;

}


using namespace pr2_laser_snapshotter;

int main(int argc, char **argv)
{
  ros::init(argc, argv, "point_cloud_srv");
  PointCloudSrv cloud_srv;

  ros::MultiThreadedSpinner spinner(2);
  spinner.spin();

  return 0;
}

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pr2_arm_navigation_perception
Author(s): Sachin Chitta
autogenerated on Fri Mar 1 16:53:26 2013