branch_estimator.h

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 *  Point Cloud Library (PCL) - www.pointclouds.org
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#pragma once
 
#include <pcl/common/common.h>
#include <pcl/common/utils.h> // pcl::utils::ignore
#include <pcl/ml/stats_estimator.h>
 
namespace pcl {
 
/** Interface for branch estimators. */
class PCL_EXPORTS BranchEstimator {
public:
  /** Destructor. */
  virtual ~BranchEstimator() = default;
 
  /** Returns the number of branches the corresponding tree has. */
  virtual std::size_t
  getNumOfBranches() const = 0;
 
  /** Computes the branch index for the specified result.
   *
   * \param[in] result the result the branch index will be computed for
   * \param[in] flag the flag corresponding to the specified result
   * \param[in] threshold the threshold used to compute the branch index
   * \param[out] branch_index the destination for the computed branch index
   */
  virtual void
  computeBranchIndex(const float result,
                     const unsigned char flag,
                     const float threshold,
                     unsigned char& branch_index) const = 0;
};
 
/** Branch estimator for binary trees where the branch is computed only from the
 *  threshold. */
class PCL_EXPORTS BinaryTreeThresholdBasedBranchEstimator : public BranchEstimator {
public:
  /** Constructor. */
  inline BinaryTreeThresholdBasedBranchEstimator() = default;
  /** Destructor. */
  inline ~BinaryTreeThresholdBasedBranchEstimator() override = default;
 
  /** Returns the number of branches the corresponding tree has. */
  inline std::size_t
  getNumOfBranches() const override
  {
    return 2;
  }
 
  /** Computes the branch index for the specified result.
   *
   * \param[in] result the result the branch index will be computed for
   * \param[in] flag the flag corresponding to the specified result
   * \param[in] threshold the threshold used to compute the branch index
   * \param[out] branch_index the destination for the computed branch index
   */
  inline void
  computeBranchIndex(const float result,
                     const unsigned char flag,
                     const float threshold,
                     unsigned char& branch_index) const override
  {
    pcl::utils::ignore(flag);
    branch_index = (result > threshold) ? 1 : 0;
  }
};
 
/** Branch estimator for ternary trees where one branch is used for missing data
 *  (indicated by flag != 0). */
class PCL_EXPORTS TernaryTreeMissingDataBranchEstimator : public BranchEstimator {
public:
  /** Constructor. */
  inline TernaryTreeMissingDataBranchEstimator() = default;
  /** Destructor. */
  inline ~TernaryTreeMissingDataBranchEstimator() override = default;
 
  /** \brief Returns the number of branches the corresponding tree has. */
  inline std::size_t
  getNumOfBranches() const override
  {
    return 3;
  }
 
  /** Computes the branch index for the specified result.
   *
   * \param[in] result the result the branch index will be computed for
   * \param[in] flag the flag corresponding to the specified result
   * \param[in] threshold the threshold used to compute the branch index
   * \param[out] branch_index the destination for the computed branch index
   */
  inline void
  computeBranchIndex(const float result,
                     const unsigned char flag,
                     const float threshold,
                     unsigned char& branch_index) const override
  {
    if (flag == 0)
      branch_index = (result > threshold) ? 1 : 0;
    else
      branch_index = 2;
  }
};
 
} // namespace pcl