Point Cloud Library (PCL)  1.12.1-dev
progressive_morphological_filter.hpp
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38 
39 #ifndef PCL_SEGMENTATION_PROGRESSIVE_MORPHOLOGICAL_FILTER_HPP_
40 #define PCL_SEGMENTATION_PROGRESSIVE_MORPHOLOGICAL_FILTER_HPP_
41 
42 #include <pcl/common/common.h>
43 #include <pcl/common/io.h>
44 #include <pcl/filters/morphological_filter.h>
45 #include <pcl/segmentation/progressive_morphological_filter.h>
46 #include <pcl/point_cloud.h>
47 #include <pcl/point_types.h>
48 
49 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
50 template <typename PointT>
52  max_window_size_ (33),
53  slope_ (0.7f),
54  max_distance_ (10.0f),
55  initial_distance_ (0.15f),
56  cell_size_ (1.0f),
57  base_ (2.0f),
58  exponential_ (true)
59 {
60 }
61 
62 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
63 template <typename PointT>
65 
66 //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
67 template <typename PointT> void
69 {
70  bool segmentation_is_possible = initCompute ();
71  if (!segmentation_is_possible)
72  {
73  deinitCompute ();
74  return;
75  }
76 
77  // Compute the series of window sizes and height thresholds
78  std::vector<float> height_thresholds;
79  std::vector<float> window_sizes;
80  int iteration = 0;
81  float window_size = 0.0f;
82  float height_threshold = 0.0f;
83 
84  while (window_size < max_window_size_)
85  {
86  // Determine the initial window size.
87  if (exponential_)
88  window_size = cell_size_ * (2.0f * std::pow (base_, iteration) + 1.0f);
89  else
90  window_size = cell_size_ * (2.0f * (iteration+1) * base_ + 1.0f);
91 
92  // Calculate the height threshold to be used in the next iteration.
93  if (iteration == 0)
94  height_threshold = initial_distance_;
95  else
96  height_threshold = slope_ * (window_size - window_sizes[iteration-1]) * cell_size_ + initial_distance_;
97 
98  // Enforce max distance on height threshold
99  if (height_threshold > max_distance_)
100  height_threshold = max_distance_;
101 
102  window_sizes.push_back (window_size);
103  height_thresholds.push_back (height_threshold);
104 
105  iteration++;
106  }
107 
108  // Ground indices are initially limited to those points in the input cloud we
109  // wish to process
110  ground = *indices_;
111 
112  // Progressively filter ground returns using morphological open
113  for (std::size_t i = 0; i < window_sizes.size (); ++i)
114  {
115  PCL_DEBUG (" Iteration %d (height threshold = %f, window size = %f)...",
116  i, height_thresholds[i], window_sizes[i]);
117 
118  // Limit filtering to those points currently considered ground returns
120  pcl::copyPointCloud<PointT> (*input_, ground, *cloud);
121 
122  // Create new cloud to hold the filtered results. Apply the morphological
123  // opening operation at the current window size.
125  pcl::applyMorphologicalOperator<PointT> (cloud, window_sizes[i], MORPH_OPEN, *cloud_f);
126 
127  // Find indices of the points whose difference between the source and
128  // filtered point clouds is less than the current height threshold.
129  Indices pt_indices;
130  for (std::size_t p_idx = 0; p_idx < ground.size (); ++p_idx)
131  {
132  float diff = (*cloud)[p_idx].z - (*cloud_f)[p_idx].z;
133  if (diff < height_thresholds[i])
134  pt_indices.push_back (ground[p_idx]);
135  }
136 
137  // Ground is now limited to pt_indices
138  ground.swap (pt_indices);
139 
140  PCL_DEBUG ("ground now has %d points\n", ground.size ());
141  }
142 
143  deinitCompute ();
144 }
145 
146 #define PCL_INSTANTIATE_ProgressiveMorphologicalFilter(T) template class pcl::ProgressiveMorphologicalFilter<T>;
147 
148 #endif // PCL_SEGMENTATION_PROGRESSIVE_MORPHOLOGICAL_FILTER_HPP_
149 
PointCloud represents the base class in PCL for storing collections of 3D points.
Definition: point_cloud.h:173
shared_ptr< PointCloud< PointT > > Ptr
Definition: point_cloud.h:413
virtual void extract(Indices &ground)
This method launches the segmentation algorithm and returns indices of points determined to be ground...
ProgressiveMorphologicalFilter()
Constructor that sets default values for member variables.
Define standard C methods and C++ classes that are common to all methods.
Defines all the PCL implemented PointT point type structures.
IndicesAllocator<> Indices
Type used for indices in PCL.
Definition: types.h:133