laser_scan_assembler.cpp

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#include "laser_geometry/laser_geometry.h"
#include "sensor_msgs/LaserScan.h"
#include "laser_assembler/base_assembler.h"
#include "filters/filter_chain.hpp"
 
using namespace laser_geometry;
using namespace std ;
 
namespace laser_assembler
{
 
class LaserScanAssembler : public BaseAssembler<sensor_msgs::LaserScan>
{
public:
  LaserScanAssembler() : BaseAssembler<sensor_msgs::LaserScan>("max_scans"), filter_chain_("sensor_msgs::LaserScan")
  {
    // ***** Set Laser Projection Method *****
    private_ns_.param("ignore_laser_skew", ignore_laser_skew_, true);
 
    // configure the filter chain from the parameter server
    filter_chain_.configure("filters", private_ns_);
 
    // Have different callbacks, depending on whether or not we want to ignore laser skews.
    if (ignore_laser_skew_)
      start("scan");
    else
    {
      start();
      skew_scan_sub_ = n_.subscribe("scan", 10, &LaserScanAssembler::scanCallback, this);
    }
  }
 
  ~LaserScanAssembler()
  {
 
  }
 
  unsigned int GetPointsInScan(const sensor_msgs::LaserScan& scan)
  {
    return (scan.ranges.size ());
  }
 
  void ConvertToCloud(const string& fixed_frame_id, const sensor_msgs::LaserScan& scan_in, sensor_msgs::PointCloud& cloud_out)
  {
    // apply filters on laser scan
    filter_chain_.update (scan_in, scan_filtered_);
 
    // convert laser scan to point cloud
    if (ignore_laser_skew_)  // Do it the fast (approximate) way
    {
      projector_.projectLaser(scan_filtered_, cloud_out);
      if (cloud_out.header.frame_id != fixed_frame_id)
        tf_->transformPointCloud(fixed_frame_id, cloud_out, cloud_out);
    }
    else                     // Do it the slower (more accurate) way
    {
      int mask = laser_geometry::channel_option::Intensity +
                 laser_geometry::channel_option::Distance +
                 laser_geometry::channel_option::Index +
                 laser_geometry::channel_option::Timestamp;
      projector_.transformLaserScanToPointCloud (fixed_frame_id, scan_filtered_, cloud_out, *tf_, mask);
    }
    return;
  }
 
  void scanCallback(const sensor_msgs::LaserScanConstPtr& laser_scan)
  {
    if (!ignore_laser_skew_)
    {
      ros::Duration cur_tolerance = ros::Duration(laser_scan->time_increment * laser_scan->ranges.size());
      if (cur_tolerance > max_tolerance_)
      {
        ROS_DEBUG("Upping tf tolerance from [%.4fs] to [%.4fs]", max_tolerance_.toSec(), cur_tolerance.toSec());
        assert(tf_filter_);
        tf_filter_->setTolerance(cur_tolerance);
        max_tolerance_ = cur_tolerance;
      }
      tf_filter_->add(laser_scan);
    }
  }
 
private:
  bool ignore_laser_skew_;
  laser_geometry::LaserProjection projector_;
 
  ros::Subscriber skew_scan_sub_;
  ros::Duration max_tolerance_;   // The longest tolerance we've needed on a scan so far
 
  filters::FilterChain<sensor_msgs::LaserScan> filter_chain_;
  mutable sensor_msgs::LaserScan scan_filtered_;
 
};
 
}
 
using namespace laser_assembler ;
 
int main(int argc, char **argv)
{
  ros::init(argc, argv, "laser_scan_assembler");
  LaserScanAssembler pc_assembler;
  ros::spin();
 
  return 0;
}