median_filter.hpp

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#pragma once
 
#include <pcl/filters/median_filter.h>
#include <pcl/common/point_tests.h> // for pcl::isFinite
 
template <typename PointT> void
pcl::MedianFilter<PointT>::applyFilter (PointCloud &output)
{
  if (!input_->isOrganized ())
  {
    PCL_ERROR ("[pcl::MedianFilter] Input cloud needs to be organized\n");
    return;
  }
 
  // Copy everything from the input cloud to the output cloud (takes care of all the fields)
  copyPointCloud (*input_, output);
 
  int height = static_cast<int> (output.height);
  int width = static_cast<int> (output.width);
  for (int y = 0; y < height; ++y)
    for (int x = 0; x < width; ++x)
      if (pcl::isFinite ((*input_)(x, y)))
      {
        std::vector<float> vals;
        vals.reserve (window_size_ * window_size_);
        // Fill in the vector of values with the depths around the interest point
        for (int y_dev = -window_size_/2; y_dev <= window_size_/2; ++y_dev)
          for (int x_dev = -window_size_/2; x_dev <= window_size_/2; ++x_dev)
          {
            if (x + x_dev >= 0 && x + x_dev < width &&
                y + y_dev >= 0 && y + y_dev < height &&
                pcl::isFinite ((*input_)(x+x_dev, y+y_dev)))
              vals.push_back ((*input_)(x+x_dev, y+y_dev).z);
          }
 
        if (vals.empty ())
          continue;
 
        // The output depth will be the median of all the depths in the window
        auto middle_it = vals.begin () + vals.size () / 2;
        std::nth_element (vals.begin (), middle_it, vals.end ());
        float new_depth = *middle_it;
        // Do not allow points to move more than the set max_allowed_movement_
        if (std::abs (new_depth - (*input_)(x, y).z) < max_allowed_movement_)
          output (x, y).z = new_depth;
        else
          output (x, y).z = (*input_)(x, y).z +
                            max_allowed_movement_ * (new_depth - (*input_)(x, y).z) / std::abs (new_depth - (*input_)(x, y).z);
      }
}