uniform_sampling.cpp

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#include <pcl/PCLPointCloud2.h>
#include <pcl/io/auto_io.h>
#include <pcl/filters/uniform_sampling.h>
#include <pcl/common/pcl_filesystem.h>
#include <pcl/console/print.h>
#include <pcl/console/parse.h>
#include <pcl/console/time.h>

#include <algorithm>
#include <string>

using namespace pcl;
using namespace pcl::io;
using namespace pcl::console;

double default_radius = 0.01;

void
printHelp (int, char **argv)
{
  print_error ("Syntax is: %s <input_point_cloud> <output_point_cloud> <options>\n", argv[0]);
  print_info ("This tool rely on the file extensions to guess the good reader/writer.\n");
  print_info ("The supported extension for the point cloud are .pcd .ply and .vtk\n");
  print_info ("  where options are:\n");
  print_info ("                     -radius X = use a leaf size of X,X,X to uniformly select 1 point per leaf (default: "); 
  print_value ("%f", default_radius); print_info (")\n");
}

bool
loadCloud (const std::string &filename, pcl::PCLPointCloud2 &cloud)
{
  TicToc tt;
  print_highlight ("Loading "); print_value ("%s ", filename.c_str ());

  tt.tic ();
  if (pcl::io::load (filename, cloud)) {
    print_error ("Cannot found input file name (%s).\n", filename.c_str ());
    return (false);
  }
  print_info ("[done, "); print_value ("%g", tt.toc ()); print_info (" ms : ");
  print_value ("%d", cloud.width * cloud.height); print_info (" points]\n");
  print_info ("Available dimensions: "); print_value ("%s\n", getFieldsList (cloud).c_str ());

  return (true);
}

void
compute (const pcl::PCLPointCloud2::ConstPtr &input, pcl::PCLPointCloud2 &output,
         double radius)
{
  // Convert data to PointCloud<T>
  PointCloud<PointXYZ>::Ptr xyz (new PointCloud<PointXYZ>);
  fromPCLPointCloud2 (*input, *xyz);

  // Estimate
  TicToc tt;
  tt.tic ();

  print_highlight (stderr, "Computing ");

  UniformSampling<PointXYZ> us(true); // extract removed indices
  us.setInputCloud(xyz);
  us.setRadiusSearch(radius);
  PointCloud<PointXYZ> temp;
  us.filter(temp);

  pcl::PointIndices removed_indices;
  // These are "fake" indices generated by initCompute(), already sorted
  auto input_indices = us.getIndices();
  // Removed indices, not guaranteed to be sorted
  us.getRemovedIndices(removed_indices);
  std::sort(removed_indices.indices.begin(), removed_indices.indices.end());
  // Compute retained indices as a set difference between all and removed
  pcl::Indices retained;
  std::set_difference(input_indices->begin(),
                      input_indices->end(),
                      removed_indices.indices.begin(),
                      removed_indices.indices.end(),
                      std::inserter(retained, retained.begin()));
  pcl::copyPointCloud(*input, retained, output);

  print_info ("[done, "); print_value ("%g", tt.toc ()); print_info (" ms : ");
  print_value ("%d", retained.size()); print_info (" points]\n");
}

void
saveCloud (const std::string &filename, const pcl::PCLPointCloud2 &output)
{
  TicToc tt;
  tt.tic ();

  print_highlight ("Saving "); print_value ("%s ", filename.c_str ());

  PCDWriter w_pcd;
  PLYWriter w_ply;
  std::string output_ext = pcl_fs::path (filename).extension ().string ();
  std::transform (output_ext.begin (), output_ext.end (), output_ext.begin (), ::tolower);

  if (output_ext == ".pcd")
  {
    w_pcd.writeBinaryCompressed (filename, output);
  }
  else if (output_ext == ".ply")
  {
    w_ply.writeBinary (filename, output);
  }
  else if (output_ext == ".vtk")
  {
    w_ply.writeBinary (filename, output);
  }
  
  print_info ("[done, "); print_value ("%g", tt.toc ()); print_info (" ms : "); print_value ("%d", output.width * output.height); print_info (" points]\n");
}

/* ---[ */
int
main (int argc, char** argv)
{
  print_info ("Uniform subsampling using UniformSampling. For more information, use: %s -h\n", argv[0]);

  if (argc < 3)
  {
    printHelp (argc, argv);
    return (-1);
  }

  // Parse the command line arguments for .pcd files
  std::vector<int> p_file_indices;
  std::vector<std::string> extension;
  extension.emplace_back(".pcd");
  extension.emplace_back(".ply");
  extension.emplace_back(".vtk");
  p_file_indices = parse_file_extension_argument (argc, argv, extension);

  if (p_file_indices.size () != 2)
  {
    print_error ("Need one input file and one output file to continue.\n");
    return (-1);
  }

  std::string input_filename = argv[p_file_indices[0]];
  std::string output_filename = argv[p_file_indices[1]];

  // Command line parsing
  double radius = default_radius;
  parse_argument (argc, argv, "-radius", radius);
  print_info ("Extracting uniform points with a leaf size of: "); 
  print_value ("%f\n", radius); 

  // Load the first file
  pcl::PCLPointCloud2::Ptr cloud (new pcl::PCLPointCloud2);
  if (!loadCloud (input_filename, *cloud))
    return (-1);

  // Perform the keypoint estimation
  pcl::PCLPointCloud2 output;
  compute (cloud, output, radius);

  // Save into the second file
  saveCloud (output_filename, output);
}