Point Cloud Library (PCL)  1.10.1-dev
uniform_sampling.h
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39 
40 #pragma once
41 
42 #include <pcl/filters/filter.h>
43 
44 #include <unordered_map>
45 
46 namespace pcl
47 {
48  /** \brief @b UniformSampling assembles a local 3D grid over a given PointCloud, and downsamples + filters the data.
49  *
50  * The @b UniformSampling class creates a *3D voxel grid* (think about a voxel
51  * grid as a set of tiny 3D boxes in space) over the input point cloud data.
52  * Then, in each *voxel* (i.e., 3D box), all the points present will be
53  * approximated (i.e., *downsampled*) with their centroid. This approach is
54  * a bit slower than approximating them with the center of the voxel, but it
55  * represents the underlying surface more accurately.
56  *
57  * \author Radu Bogdan Rusu
58  * \ingroup filters
59  */
60  template <typename PointT>
61  class UniformSampling: public Filter<PointT>
62  {
63  using PointCloud = typename Filter<PointT>::PointCloud;
64 
71 
72  public:
75 
76  /** \brief Empty constructor. */
77  UniformSampling (bool extract_removed_indices = false) :
78  Filter<PointT>(extract_removed_indices),
79  leaves_ (),
80  leaf_size_ (Eigen::Vector4f::Zero ()),
81  inverse_leaf_size_ (Eigen::Vector4f::Zero ()),
82  min_b_ (Eigen::Vector4i::Zero ()),
83  max_b_ (Eigen::Vector4i::Zero ()),
84  div_b_ (Eigen::Vector4i::Zero ()),
85  divb_mul_ (Eigen::Vector4i::Zero ()),
86  search_radius_ (0)
87  {
88  filter_name_ = "UniformSampling";
89  }
90 
91  /** \brief Destructor. */
93  {
94  leaves_.clear();
95  }
96 
97  /** \brief Set the 3D grid leaf size.
98  * \param radius the 3D grid leaf size
99  */
100  virtual inline void
101  setRadiusSearch (double radius)
102  {
103  leaf_size_[0] = leaf_size_[1] = leaf_size_[2] = static_cast<float> (radius);
104  // Avoid division errors
105  if (leaf_size_[3] == 0)
106  leaf_size_[3] = 1;
107  // Use multiplications instead of divisions
108  inverse_leaf_size_ = Eigen::Array4f::Ones () / leaf_size_.array ();
109  search_radius_ = radius;
110  }
111 
112  protected:
113  /** \brief Simple structure to hold an nD centroid and the number of points in a leaf. */
114  struct Leaf
115  {
116  Leaf () : idx (-1) { }
117  int idx;
118  };
119 
120  /** \brief The 3D grid leaves. */
121  std::unordered_map<std::size_t, Leaf> leaves_;
122 
123  /** \brief The size of a leaf. */
124  Eigen::Vector4f leaf_size_;
125 
126  /** \brief Internal leaf sizes stored as 1/leaf_size_ for efficiency reasons. */
127  Eigen::Array4f inverse_leaf_size_;
128 
129  /** \brief The minimum and maximum bin coordinates, the number of divisions, and the division multiplier. */
130  Eigen::Vector4i min_b_, max_b_, div_b_, divb_mul_;
131 
132  /** \brief The nearest neighbors search radius for each point. */
134 
135  /** \brief Downsample a Point Cloud using a voxelized grid approach
136  * \param[out] output the resultant point cloud message
137  */
138  void
139  applyFilter (PointCloud &output) override;
140  };
141 }
142 
143 #ifdef PCL_NO_PRECOMPILE
144 #include <pcl/filters/impl/uniform_sampling.hpp>
145 #endif
Eigen::Vector4i max_b_
Eigen::Vector4i divb_mul_
std::unordered_map< std::size_t, Leaf > leaves_
The 3D grid leaves.
Eigen::Vector4f leaf_size_
The size of a leaf.
Definition: bfgs.h:9
double search_radius_
The nearest neighbors search radius for each point.
void applyFilter(PointCloud &output) override
Downsample a Point Cloud using a voxelized grid approach.
Eigen::Vector4i div_b_
UniformSampling(bool extract_removed_indices=false)
Empty constructor.
Filter represents the base filter class.
Definition: filter.h:83
Eigen::Vector4i min_b_
The minimum and maximum bin coordinates, the number of divisions, and the division multiplier...
shared_ptr< Filter< PointT > > Ptr
Definition: filter.h:86
PointCloud represents the base class in PCL for storing collections of 3D points. ...
~UniformSampling()
Destructor.
std::string filter_name_
The filter name.
Definition: filter.h:161
shared_ptr< const Filter< PointT > > ConstPtr
Definition: filter.h:87
A point structure representing Euclidean xyz coordinates, and the RGB color.
virtual void setRadiusSearch(double radius)
Set the 3D grid leaf size.
Eigen::Array4f inverse_leaf_size_
Internal leaf sizes stored as 1/leaf_size_ for efficiency reasons.
boost::shared_ptr< T > shared_ptr
Alias for boost::shared_ptr.
Definition: memory.h:81
Simple structure to hold an nD centroid and the number of points in a leaf.
UniformSampling assembles a local 3D grid over a given PointCloud, and downsamples + filters the data...