Point Cloud Library (PCL) 1.12.0
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random_sample.hpp
1/*
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34 * $Id: extract_indices.hpp 1897 2011-07-26 20:35:49Z rusu $
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37
38#ifndef PCL_FILTERS_IMPL_RANDOM_SAMPLE_H_
39#define PCL_FILTERS_IMPL_RANDOM_SAMPLE_H_
40
41#include <pcl/filters/random_sample.h>
42
43
44///////////////////////////////////////////////////////////////////////////////
45template<typename PointT>
46void
48{
49 std::size_t N = indices_->size ();
50 std::size_t sample_size = negative_ ? N - sample_ : sample_;
51 // If sample size is 0 or if the sample size is greater then input cloud size
52 // then return all indices
53 if (sample_size >= N)
54 {
55 indices = *indices_;
56 removed_indices_->clear ();
57 }
58 else
59 {
60 // Resize output indices to sample size
61 indices.resize (sample_size);
62 if (extract_removed_indices_)
63 removed_indices_->resize (N - sample_size);
64
65 // Set random seed so derived indices are the same each time the filter runs
66 std::srand (seed_);
67
68 // Algorithm S
69 std::size_t i = 0;
70 std::size_t index = 0;
71 std::vector<bool> added;
72 if (extract_removed_indices_)
73 added.resize (indices_->size (), false);
74 std::size_t n = sample_size;
75 while (n > 0)
76 {
77 // Step 1: [Generate U.] Generate a random variate U that is uniformly distributed between 0 and 1.
78 const float U = unifRand ();
79 // Step 2: [Test.] If N * U > n, go to Step 4.
80 if ((N * U) <= n)
81 {
82 // Step 3: [Select.] Select the next record in the file for the sample, and set n : = n - 1.
83 if (extract_removed_indices_)
84 added[index] = true;
85 indices[i++] = (*indices_)[index];
86 --n;
87 }
88 // Step 4: [Don't select.] Skip over the next record (do not include it in the sample).
89 // Set N : = N - 1.
90 --N;
91 ++index;
92 // If n > 0, then return to Step 1; otherwise, the sample is complete and the algorithm terminates.
93 }
94
95 // Now populate removed_indices_ appropriately
96 if (extract_removed_indices_)
97 {
98 std::size_t ri = 0;
99 for (std::size_t i = 0; i < added.size (); i++)
100 {
101 if (!added[i])
102 {
103 (*removed_indices_)[ri++] = (*indices_)[i];
104 }
105 }
106 }
107 }
108}
109
110#define PCL_INSTANTIATE_RandomSample(T) template class PCL_EXPORTS pcl::RandomSample<T>;
111
112#endif // PCL_FILTERS_IMPL_RANDOM_SAMPLE_H_
void applyFilter(Indices &indices) override
Sample of point indices.
IndicesAllocator<> Indices
Type used for indices in PCL.
Definition types.h:133