convolution.h

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#ifndef PCL_2D_CONVOLUTION_H
#define PCL_2D_CONVOLUTION_H

#include <pcl/pcl_base.h>
#include <pcl/filters/filter.h>
#include <pcl/point_types.h>

namespace pcl
{
  /**
   * This typedef is used to represent a point cloud containing edge information
   */
  struct PointXYZIEdge
  {
    PCL_ADD_POINT4D;                    // preferred way of adding a XYZ+padding
    float magnitude;
    float direction;
    float magnitude_x;
    float magnitude_y;
    EIGEN_MAKE_ALIGNED_OPERATOR_NEW     // make sure our new allocators are aligned
  } EIGEN_ALIGN16;                    // enforce SSE padding for correct memory alignment

  /** \brief A 2D convolution class. */ 
  template <typename PointT>
  class Convolution : public Filter<PointT>
  {
    public:
      using Filter<PointT>::input_;
      
      /**
       * Extra pixels are added to the input image so that convolution can be performed over the entire image.
       *
       * (kernel_height/2) rows are added before the first row and after the last row
       * (kernel_width/2) columns are added before the first column and after the last column
       * border options define what values are set for these extra rows and columns
       *
       * Assume that the three rows of right edge of the image looks like this:
       *    .. 3 2 1
       *    .. 6 5 4
       *    .. 9 8 7
       *
       * BOUNDARY_OPTION_CLAMP : the extra pixels are set to the pixel value of the boundary pixel
       *    This option makes it seem as if it were:
       *    .. 3 2 1| 1 1 1 ..
       *    .. 6 5 4| 4 4 4 ..
       *    .. 9 8 7| 7 7 7 ..
       *
       * BOUNDARY_OPTION_MIRROR : the input image is mirrored at the boundary.
       *    This option makes it seem as if it were:
       *    .. 3 2 1| 1 2 3 ..
       *    .. 6 5 4| 4 5 6 ..
       *    .. 9 8 7| 7 8 9 ..
       *
       * BOUNDARY_OPTION_ZERO_PADDING : the extra pixels are simply set to 0
       *    This option makes it seem as if it were:
       *    .. 3 2 1| 0 0 0 ..
       *    .. 6 5 4| 0 0 0 ..
       *    .. 9 8 7| 0 0 0 ..
       *
       * Note that the input image is not actually extended in size. Instead, based on these options,
       * the convolution is performed differently at the border pixels.
       */
      enum BOUNDARY_OPTIONS_ENUM
      {
        BOUNDARY_OPTION_CLAMP,
        BOUNDARY_OPTION_MIRROR,
        BOUNDARY_OPTION_ZERO_PADDING
      };

      Convolution ()
      {
        boundary_options_ = BOUNDARY_OPTION_CLAMP;
      }

      /** \brief Sets the kernel to be used for convolution
        * \param[in] kernel convolution kernel passed by reference
        */
      inline void 
      setKernel (const pcl::PointCloud<PointT> &kernel)
      {
        kernel_ = kernel;
      }

      /**
        * \param[in] boundary_options enum indicating the boundary options to be used for convolution
        */
      inline void 
      setBoundaryOptions (BOUNDARY_OPTIONS_ENUM boundary_options)
      {
        boundary_options_ = boundary_options;
      }

      /** \brief Performs 2D convolution of the input point cloud with the kernel.
        * Uses clamp as the default boundary option.
        * \param[out] output Output point cloud passed by reference
        */
      void 
      filter (pcl::PointCloud<PointT> &output);

    protected:
      /** \brief This is an over-ride function for the pcl::Filter interface. */
      void 
      applyFilter (pcl::PointCloud<PointT> &) {}

    private:
      BOUNDARY_OPTIONS_ENUM boundary_options_;
      pcl::PointCloud<PointT> kernel_;
  };
}

#include <pcl/2d/impl/convolution.hpp>

POINT_CLOUD_REGISTER_POINT_STRUCT (pcl::PointXYZIEdge,
    (float, x, x)
    (float, y, y)
    (float, z, z)
    (float, magnitude, magnitude)
    (float, direction, direction)
    (float, magnitude_x, magnitude_x)
    (float, magnitude_y, magnitude_y)
)
#endif // PCL_2D_CONVOLUTION_2D_H