laser_processor.cpp

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#include <laser_processor.h>
#include <stdexcept>

#include <list>
#include <set>

namespace laser_processor
{
Sample* Sample::Extract(int ind, const sensor_msgs::LaserScan& scan)
{
  Sample* s = new Sample();

  s->index = ind;
  s->range = scan.ranges[ind];
  s->x = cos(scan.angle_min + ind * scan.angle_increment) * s->range;
  s->y = sin(scan.angle_min + ind * scan.angle_increment) * s->range;
  if (s->range > scan.range_min && s->range < scan.range_max)
    return s;
  else
  {
    delete s;
    return NULL;
  }
}

void SampleSet::clear()
{
  for (SampleSet::iterator i = begin();
       i != end();
       i++)
  {
    delete(*i);
  }
  set<Sample*, CompareSample>::clear();
}

void SampleSet::appendToCloud(sensor_msgs::PointCloud& cloud, int r, int g, int b)
{
  float color_val = 0;

  int rgb = (r << 16) | (g << 8) | b;
  color_val = *reinterpret_cast<float*>(&rgb);

  for (iterator sample_iter = begin();
       sample_iter != end();
       sample_iter++)
  {
    geometry_msgs::Point32 point;
    point.x = (*sample_iter)->x;
    point.y = (*sample_iter)->y;
    point.z = 0;

    cloud.points.push_back(point);

    if (cloud.channels[0].name == "rgb")
      cloud.channels[0].values.push_back(color_val);
  }
}

tf::Point SampleSet::center()
{
  float x_mean = 0.0;
  float y_mean = 0.0;
  for (iterator i = begin();
       i != end();
       i++)

  {
    x_mean += ((*i)->x) / size();
    y_mean += ((*i)->y) / size();
  }

  return tf::Point(x_mean, y_mean, 0.0);
}

void ScanMask::addScan(sensor_msgs::LaserScan& scan)
{
  if (!filled)
  {
    angle_min = scan.angle_min;
    angle_max = scan.angle_max;
    size      = scan.ranges.size();
    filled    = true;
  }
  else if (angle_min != scan.angle_min     ||
           angle_max != scan.angle_max     ||
           size      != scan.ranges.size())
  {
    throw std::runtime_error("laser_scan::ScanMask::addScan: inconsistantly sized scans added to mask");
  }

  for (uint32_t i = 0; i < scan.ranges.size(); i++)
  {
    Sample* s = Sample::Extract(i, scan);

    if (s != NULL)
    {
      SampleSet::iterator m = mask_.find(s);

      if (m != mask_.end())
      {
        if ((*m)->range > s->range)
        {
          delete(*m);
          mask_.erase(m);
          mask_.insert(s);
        }
        else
        {
          delete s;
        }
      }
      else
      {
        mask_.insert(s);
      }
    }
  }
}

bool ScanMask::hasSample(Sample* s, float thresh)
{
  if (s != NULL)
  {
    SampleSet::iterator m = mask_.find(s);
    if (m != mask_.end())
      if (((*m)->range - thresh) < s->range)
        return true;
  }
  return false;
}

ScanProcessor::ScanProcessor(const sensor_msgs::LaserScan& scan, ScanMask& mask_, float mask_threshold)
{
  scan_ = scan;

  SampleSet* cluster = new SampleSet;
  cluster->header = scan.header;

  for (uint32_t i = 0; i < scan.ranges.size(); i++)
  {
    Sample* s = Sample::Extract(i, scan);

    if (s != NULL)
    {
      if (!mask_.hasSample(s, mask_threshold))
      {
        cluster->insert(s);
      }
      else
      {
        delete s;
      }
    }
  }

  clusters_.push_back(cluster);
}

ScanProcessor::~ScanProcessor()
{
  for (std::list<SampleSet*>::iterator c = clusters_.begin();
       c != clusters_.end();
       c++)
    delete(*c);
}

void ScanProcessor::removeLessThan(uint32_t num)
{
  std::list<SampleSet*>::iterator c_iter = clusters_.begin();
  while (c_iter != clusters_.end())
  {
    if ((*c_iter)->size() < num)
    {
      delete(*c_iter);
      clusters_.erase(c_iter++);
    }
    else
    {
      ++c_iter;
    }
  }
}

void ScanProcessor::splitConnected(float thresh)
{
  std::list<SampleSet*> tmp_clusters;

  std::list<SampleSet*>::iterator c_iter = clusters_.begin();

  // For each cluster
  while (c_iter != clusters_.end())
  {
    // Go through the entire list
    while ((*c_iter)->size() > 0)
    {
      // Take the first element
      SampleSet::iterator s_first = (*c_iter)->begin();

      // Start a new queue
      std::list<Sample*> sample_queue;
      sample_queue.push_back(*s_first);

      (*c_iter)->erase(s_first);

      // Grow until we get to the end of the queue
      std::list<Sample*>::iterator s_q = sample_queue.begin();
      while (s_q != sample_queue.end())
      {
        int expand = static_cast<int>(asin(thresh / (*s_q)->range) / scan_.angle_increment);

        SampleSet::iterator s_rest = (*c_iter)->begin();

        while ((s_rest != (*c_iter)->end() &&
                (*s_rest)->index < (*s_q)->index + expand))
        {
          if ((*s_rest)->range - (*s_q)->range > thresh)
          {
            break;
          }
          else if (sqrt(pow((*s_q)->x - (*s_rest)->x, 2.0f) + pow((*s_q)->y - (*s_rest)->y, 2.0f)) < thresh)
          {
            sample_queue.push_back(*s_rest);
            (*c_iter)->erase(s_rest++);
            break;
          }
          else
          {
            ++s_rest;
          }
        }
        s_q++;
      }

      // Move all the samples into the new cluster
      SampleSet* c = new SampleSet;
      c->header = (*c_iter)->header;
      for (s_q = sample_queue.begin(); s_q != sample_queue.end(); s_q++)
        c->insert(*s_q);

      // Store the temporary clusters
      tmp_clusters.push_back(c);
    }

    // Now that c_iter is empty, we can delete
    delete(*c_iter);

    // And remove from the map
    clusters_.erase(c_iter++);
  }

  clusters_.insert(clusters_.begin(), tmp_clusters.begin(), tmp_clusters.end());
}

};  // namespace laser_processor