Add: create local 2D grid over input point cloud and downsample to minim...

filters/CMakeLists.txt

@@ -36,6 +36,7 @@ if(build)
         src/median_filter.cpp
 	src/voxel_grid_occlusion_estimation.cpp
 	    src/normal_refinement.cpp
+        src/grid_minimum.cpp
         )
 
     set(incs
@@ -71,6 +72,7 @@ if(build)
         "include/pcl/${SUBSYS_NAME}/covariance_sampling.h"
         "include/pcl/${SUBSYS_NAME}/median_filter.h"
         "include/pcl/${SUBSYS_NAME}/normal_refinement.h"
+        "include/pcl/${SUBSYS_NAME}/grid_minimum.h"
         )
 
     set(impl_incs
@@ -103,6 +105,7 @@ if(build)
         "include/pcl/${SUBSYS_NAME}/impl/covariance_sampling.hpp"
         "include/pcl/${SUBSYS_NAME}/impl/median_filter.hpp"
         "include/pcl/${SUBSYS_NAME}/impl/normal_refinement.hpp"
+        "include/pcl/${SUBSYS_NAME}/impl/grid_minimum.hpp"
         )
 
     set(LIB_NAME "pcl_${SUBSYS_NAME}")

filters/include/pcl/filters/grid_minimum.h

@@ -0,0 +1,208 @@
+/*
+ * Software License Agreement (BSD License)
+ *
+ *  Point Cloud Library (PCL) - www.pointclouds.org
+ *  Copyright (c) 2009-2012, Willow Garage, Inc.
+ *  Copyright (c) 2012-, Open Perception, Inc.
+ *  Copyright (c) 2014, RadiantBlue Technologies, Inc.
+ *
+ *  All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions
+ *  are met:
+ *
+ *   * Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *   * Redistributions in binary form must reproduce the above
+ *     copyright notice, this list of conditions and the following
+ *     disclaimer in the documentation and/or other materials provided
+ *     with the distribution.
+ *   * Neither the name of the copyright holder(s) nor the names of its
+ *     contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ *  COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ *  LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ *  CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ *  ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *  POSSIBILITY OF SUCH DAMAGE.
+ *
+ * $Id$
+ *
+ */
+
+#ifndef PCL_FILTERS_VOXEL_GRID_MINIMUM_H_
+#define PCL_FILTERS_VOXEL_GRID_MINIMUM_H_
+
+#include <pcl/filters/boost.h>
+#include <pcl/filters/filter.h>
+#include <pcl/filters/filter_indices.h>
+#include <pcl/filters/voxel_grid.h>
+#include <map>
+
+namespace pcl
+{
+  /** \brief GridMinimum assembles a local 2D grid over a given PointCloud, and downsamples the data.
+    *
+    * The GridMinimum class creates a *2D grid* over the input point cloud
+    * data. Then, in each *cell* (i.e., 2D grid element), all the points
+    * present will be *downsampled* with the minimum z value. This grid minimum
+    * can be useful in a number of topographic processing tasks such as crudely
+    * estimating ground returns, especially under foliage.
+    *
+    * \author Bradley J Chambers
+    * \ingroup filters
+    */
+  template <typename PointT>
+  class GridMinimum: public FilterIndices<PointT>
+  {
+    protected:
+      using Filter<PointT>::filter_name_;
+      using Filter<PointT>::getClassName;
+      using Filter<PointT>::input_;
+      using Filter<PointT>::indices_;
+
+      typedef typename FilterIndices<PointT>::PointCloud PointCloud;
+
+    public:
+      /** \brief Empty constructor. */
+      GridMinimum () :
+        leaf_size_ (Eigen::Vector4f::Zero ()),
+        inverse_leaf_size_ (Eigen::Array4f::Zero ()),
+        min_b_ (Eigen::Vector4i::Zero ()),
+        max_b_ (Eigen::Vector4i::Zero ()),
+        div_b_ (Eigen::Vector4i::Zero ()),
+        divb_mul_ (Eigen::Vector4i::Zero ()),
+        min_points_per_grid_ (0)
+      {
+        filter_name_ = "GridMinimum";
+      }
+
+      /** \brief Destructor. */
+      virtual ~GridMinimum ()
+      {
+      }
+
+      /** \brief Set the grid leaf size.
+        * \param[in] leaf_size the grid leaf size
+        */
+      inline void
+      setLeafSize (const Eigen::Vector4f &leaf_size)
+      {
+        leaf_size_ = leaf_size;
+        // Avoid division errors
+        if (leaf_size_[2] == 0)
+          leaf_size_[2] = 1;
+        if (leaf_size_[3] == 0)
+          leaf_size_[3] = 1;
+        // Use multiplications instead of divisions
+        inverse_leaf_size_ = Eigen::Array4f::Ones () / leaf_size_.array ();
+      }
+
+      /** \brief Set the grid leaf size.
+        * \param[in] lx the leaf size for X
+        * \param[in] ly the leaf size for Y
+        */
+      inline void
+      setLeafSize (float lx, float ly)
+      {
+        leaf_size_[0] = lx; leaf_size_[1] = ly;
+        // Avoid division errors
+        if (leaf_size_[2] == 0)
+          leaf_size_[2] = 1;
+        if (leaf_size_[3] == 0)
+          leaf_size_[3] = 1;
+        // Use multiplications instead of divisions
+        inverse_leaf_size_ = Eigen::Array4f::Ones () / leaf_size_.array ();
+      }
+
+      /** \brief Get the grid leaf size. */
+      inline Eigen::Vector3f
+      getLeafSize () { return (leaf_size_.head<3> ()); }
+
+      /** \brief Set the minimum number of points required for a grid cell to be used.
+        * \param[in] min_points_per_voxel the minimum number of points for required for a cell to be used
+        */
+      inline void
+      setMinimumPointsNumberPerGrid (unsigned int min_points_per_grid) { min_points_per_grid_ = min_points_per_grid; }
+
+      /** \brief Return the minimum number of points required for a grid cell to be used.
+       */
+      inline unsigned int
+      getMinimumPointsNumberPerGrid () { return min_points_per_grid_; }
+
+      /** \brief Get the minimum coordinates of the bounding box (after
+        * filtering is performed).
+        */
+      inline Eigen::Vector3i
+      getMinBoxCoordinates () { return (min_b_.head<3> ()); }
+
+      /** \brief Get the maximum coordinates of the bounding box (after
+        * filtering is performed).
+        */
+      inline Eigen::Vector3i
+      getMaxBoxCoordinates () { return (max_b_.head<3> ()); }
+
+      /** \brief Get the number of divisions along all 3 axes (after filtering
+        * is performed).
+        */
+      inline Eigen::Vector3i
+      getNrDivisions () { return (div_b_.head<3> ()); }
+
+      /** \brief Get the multipliers to be applied to the grid coordinates in
+        * order to find the centroid index (after filtering is performed).
+        */
+      inline Eigen::Vector3i
+      getDivisionMultiplier () { return (divb_mul_.head<3> ()); }
+
+    protected:
+      /** \brief The size of a leaf. */
+      Eigen::Vector4f leaf_size_;
+
+      /** \brief Internal leaf sizes stored as 1/leaf_size_ for efficiency reasons. */
+      Eigen::Array4f inverse_leaf_size_;
+
+      /** \brief Minimum number of points per grid cell for the minimum to be computed */
+      unsigned int min_points_per_grid_;
+
+      /** \brief The minimum and maximum bin coordinates, the number of divisions, and the division multiplier. */
+      Eigen::Vector4i min_b_, max_b_, div_b_, divb_mul_;
+
+      /** \brief Downsample a Point Cloud using a 2D grid approach
+        * \param[out] output the resultant point cloud message
+        */
+      void
+      applyFilter (PointCloud &output);
+
+      /** \brief Filtered results are indexed by an indices array.
+        * \param[out] indices The resultant indices.
+        */
+      void
+      applyFilter (std::vector<int> &indices)
+      {
+        applyFilterIndices (indices);
+      }
+
+      /** \brief Filtered results are indexed by an indices array.
+        * \param[out] indices The resultant indices.
+        */
+      void
+      applyFilterIndices (std::vector<int> &indices);
+
+  };
+}
+
+#ifdef PCL_NO_PRECOMPILE
+#include <pcl/filters/impl/grid_minimum.hpp>
+#endif
+
+#endif  //#ifndef PCL_FILTERS_VOXEL_GRID_MINIMUM_H_
+