Implements the well known Region Growing algorithm used for segmentation based on color of points. Description can be found in the article "Color-based segmentation of point clouds" by Qingming Zhan, Yubin Liang, Yinghui Xiao. More...

#include <region_growing_rgb.h>

Inheritance diagram for pcl::RegionGrowingRGB< PointT, NormalT >:

[legend]

List of all members.

Public Member Functions
virtual void	extract (std::vector< pcl::PointIndices > &clusters)
	This method launches the segmentation algorithm and returns the clusters that were obtained during the segmentation.
float	getDistanceThreshold () const
	Returns the distance threshold. If the distance between two points is less or equal to distance threshold value, then those points assumed to be neighbouring points.
bool	getNormalTestFlag () const
	Returns the flag that signalize if the smoothness test is turned on/off.
unsigned int	getNumberOfRegionNeighbours () const
	Returns the number of nearest neighbours used for searching K nearest segments. Note that here it refers to the segments(not the points).
float	getPointColorThreshold () const
	Returns the color threshold value used for testing if points belong to the same region.
float	getRegionColorThreshold () const
	Returns the color threshold value used for testing if regions can be merged.
virtual void	getSegmentFromPoint (int index, pcl::PointIndices &cluster)
	For a given point this function builds a segment to which it belongs and returns this segment.
	RegionGrowingRGB ()
	Constructor that sets default values for member variables.
virtual void	setCurvatureTestFlag (bool value)
	Allows to turn on/off the curvature test.
void	setDistanceThreshold (float thresh)
	Allows to set distance threshold.
void	setNormalTestFlag (bool value)
	Allows to turn on/off the smoothness test.
void	setNumberOfRegionNeighbours (unsigned int nghbr_number)
	This method allows to set the number of neighbours that is used for finding neighbouring segments. Neighbouring segments are needed for the merging process.
void	setPointColorThreshold (float thresh)
	This method specifies the threshold value for color test between the points. This kind of testing is made at the first stage of the algorithm(region growing). If the difference between points color is less than threshold value, then they are considered to be in the same region.
void	setRegionColorThreshold (float thresh)
	This method specifies the threshold value for color test between the regions. This kind of testing is made at the second stage of the algorithm(region merging). If the difference between segments color is less than threshold value, then they are merged together.
virtual void	setResidualTestFlag (bool value)
	Allows to turn on/off the residual test.
virtual	~RegionGrowingRGB ()
	Destructor that frees memory.
Protected Member Functions
void	applyRegionMergingAlgorithm ()
	This function implements the merging algorithm described in the article "Color-based segmentation of point clouds" by Qingming Zhan, Yubin Liang, Yinghui Xiao.
void	assembleRegions (std::vector< unsigned int > &num_pts_in_region, int num_regions)
	This function simply assembles the regions from list of point labels.
float	calculateColorimetricalDifference (std::vector< unsigned int > &first_color, std::vector< unsigned int > &second_color) const
	This method calculates the colorimetrical difference between two points. In this case it simply returns the euclidean distance between two colors.
virtual void	findPointNeighbours ()
	This method finds KNN for each point and saves them to the array because the algorithm needs to find KNN a few times.
void	findRegionNeighbours (std::vector< std::vector< std::pair< float, int > > > &neighbours_out, std::vector< std::vector< int > > &regions_in)
	This method assembles the array containing neighbours of each homogeneous region. Homogeneous region is the union of some segments. This array is used when the regions with a few points need to be merged with the neighbouring region.
void	findRegionsKNN (int index, int nghbr_number, std::vector< int > &nghbrs, std::vector< float > &dist)
	This method finds K nearest neighbours of the given segment.
void	findSegmentNeighbours ()
	This method simply calls the findRegionsKNN for each segment and saves the results for later use.
virtual bool	prepareForSegmentation ()
	This method simply checks if it is possible to execute the segmentation algorithm with the current settings. If it is possible then it returns true.
virtual bool	validatePoint (int initial_seed, int point, int nghbr, bool &is_a_seed) const
	This function is checking if the point with index 'nghbr' belongs to the segment. If so, then it returns true. It also checks if this point can serve as the seed.
Protected Attributes
float	color_p2p_threshold_
	Thershold used in color test for points.
float	color_r2r_threshold_
	Thershold used in color test for regions.
float	distance_threshold_
	Threshold that tells which points we need to assume neighbouring.
std::vector< std::vector< float > >	point_distances_
	Stores distances for the point neighbours from point_neighbours_.
unsigned int	region_neighbour_number_
	Number of neighbouring segments to find.
std::vector< std::vector< float > >	segment_distances_
	Stores distances for the segment neighbours from segment_neighbours_.
std::vector< int >	segment_labels_
	Stores new indices for segments that were obtained at the region growing stage.
std::vector< std::vector< int > >	segment_neighbours_
	Stores the neighboures for the corresponding segments.

Detailed Description

template<typename PointT, typename NormalT = pcl::Normal>
class pcl::RegionGrowingRGB< PointT, NormalT >

Implements the well known Region Growing algorithm used for segmentation based on color of points. Description can be found in the article "Color-based segmentation of point clouds" by Qingming Zhan, Yubin Liang, Yinghui Xiao.

Definition at line 54 of file region_growing_rgb.h.

Constructor & Destructor Documentation

template<typename PointT , typename NormalT >

pcl::RegionGrowingRGB< PointT, NormalT >::RegionGrowingRGB ( )

Constructor that sets default values for member variables.

Definition at line 51 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

pcl::RegionGrowingRGB< PointT, NormalT >::~RegionGrowingRGB ( ) [virtual]

Destructor that frees memory.

Definition at line 69 of file region_growing_rgb.hpp.

Member Function Documentation

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::applyRegionMergingAlgorithm ( ) [protected]

This function implements the merging algorithm described in the article "Color-based segmentation of point clouds" by Qingming Zhan, Yubin Liang, Yinghui Xiao.

Definition at line 367 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::assembleRegions	(	std::vector< unsigned int > &	num_pts_in_region,
		int	num_regions
	)		`[protected]`

This function simply assembles the regions from list of point labels.

Parameters:

[in]	num_pts_in_region	for each final region it stores the corresponding number of points in it
[in]	num_regions	number of regions to assemble

Definition at line 564 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

float pcl::RegionGrowingRGB< PointT, NormalT >::calculateColorimetricalDifference	(	std::vector< unsigned int > &	first_color,
		std::vector< unsigned int > &	second_color
	)		const `[protected]`

This method calculates the colorimetrical difference between two points. In this case it simply returns the euclidean distance between two colors.

Parameters:

[in]	first_color	the color of the first point
[in]	second_color	the color of the second point

Definition at line 519 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::extract ( std::vector< pcl::PointIndices > & clusters ) [virtual]

This method launches the segmentation algorithm and returns the clusters that were obtained during the segmentation.

Parameters:

[out] clusters clusters that were obtained. Each cluster is an array of point indices.

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 163 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::findPointNeighbours ( ) [protected, virtual]

This method finds KNN for each point and saves them to the array because the algorithm needs to find KNN a few times.

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 271 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::findRegionNeighbours	(	std::vector< std::vector< std::pair< float, int > > > &	neighbours_out,
		std::vector< std::vector< int > > &	regions_in
	)		`[protected]`

This method assembles the array containing neighbours of each homogeneous region. Homogeneous region is the union of some segments. This array is used when the regions with a few points need to be merged with the neighbouring region.

Parameters:

[out]	neighbours_out	vector of lists of neighbours for every homogeneous region
[in]	regions_in	vector of lists, each list contains indices of segments that belong to the corresponding homogeneous region.

Definition at line 530 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::findRegionsKNN	(	int	index,
		int	nghbr_number,
		std::vector< int > &	nghbrs,
		std::vector< float > &	dist
	)		`[protected]`

This method finds K nearest neighbours of the given segment.

Parameters:

[in]	index	index of the segment for which neighbours will be found
[in]	nghbr_number	the number of neighbours to find
[out]	nghbrs	the array of indices of the neighbours that were found
[out]	dist	the array of distances to the corresponding neighbours

Definition at line 312 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::findSegmentNeighbours ( ) [protected]

This method simply calls the findRegionsKNN for each segment and saves the results for later use.

Definition at line 293 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

float pcl::RegionGrowingRGB< PointT, NormalT >::getDistanceThreshold ( ) const

Returns the distance threshold. If the distance between two points is less or equal to distance threshold value, then those points assumed to be neighbouring points.

Definition at line 107 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

bool pcl::RegionGrowingRGB< PointT, NormalT >::getNormalTestFlag ( ) const

Returns the flag that signalize if the smoothness test is turned on/off.

Definition at line 135 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

unsigned int pcl::RegionGrowingRGB< PointT, NormalT >::getNumberOfRegionNeighbours ( ) const

Returns the number of nearest neighbours used for searching K nearest segments. Note that here it refers to the segments(not the points).

Definition at line 121 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

float pcl::RegionGrowingRGB< PointT, NormalT >::getPointColorThreshold ( ) const

Returns the color threshold value used for testing if points belong to the same region.

Definition at line 79 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

float pcl::RegionGrowingRGB< PointT, NormalT >::getRegionColorThreshold ( ) const

Returns the color threshold value used for testing if regions can be merged.

Definition at line 93 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::getSegmentFromPoint	(	int	index,
		pcl::PointIndices &	cluster
	)		`[virtual]`

For a given point this function builds a segment to which it belongs and returns this segment.

Parameters:

[in] index index of the initial point which will be the seed for growing a segment.

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 679 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

bool pcl::RegionGrowingRGB< PointT, NormalT >::prepareForSegmentation ( ) [protected, virtual]

This method simply checks if it is possible to execute the segmentation algorithm with the current settings. If it is possible then it returns true.

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 216 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setCurvatureTestFlag ( bool value ) [virtual]

Allows to turn on/off the curvature test.

Parameters:

[in] value new value for curvature test. If set to true then the test will be turned on

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 149 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setDistanceThreshold ( float thresh )

Allows to set distance threshold.

Parameters:

[in] thresh new threshold value for neighbour test

Definition at line 114 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setNormalTestFlag ( bool value )

Allows to turn on/off the smoothness test.

Parameters:

[in] value new value for normal/smoothness test. If set to true then the test will be turned on

Definition at line 142 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setNumberOfRegionNeighbours ( unsigned int nghbr_number )

This method allows to set the number of neighbours that is used for finding neighbouring segments. Neighbouring segments are needed for the merging process.

Parameters:

[in] nghbr_number the number of neighbouring segments to find

Definition at line 128 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setPointColorThreshold ( float thresh )

This method specifies the threshold value for color test between the points. This kind of testing is made at the first stage of the algorithm(region growing). If the difference between points color is less than threshold value, then they are considered to be in the same region.

Parameters:

[in] thresh new threshold value for color test

Definition at line 86 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setRegionColorThreshold ( float thresh )

This method specifies the threshold value for color test between the regions. This kind of testing is made at the second stage of the algorithm(region merging). If the difference between segments color is less than threshold value, then they are merged together.

Parameters:

[in] thresh new threshold value for color test

Definition at line 100 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

void pcl::RegionGrowingRGB< PointT, NormalT >::setResidualTestFlag ( bool value ) [virtual]

Allows to turn on/off the residual test.

Parameters:

[in] value new value for residual test. If set to true then the test will be turned on

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 156 of file region_growing_rgb.hpp.

template<typename PointT , typename NormalT >

bool pcl::RegionGrowingRGB< PointT, NormalT >::validatePoint	(	int	initial_seed,
		int	point,
		int	nghbr,
		bool &	is_a_seed
	)		const `[protected, virtual]`

This function is checking if the point with index 'nghbr' belongs to the segment. If so, then it returns true. It also checks if this point can serve as the seed.

Parameters:

[in]	initial_seed	index of the initial point that was passed to the growRegion() function
[in]	point	index of the current seed point
[in]	nghbr	index of the point that is neighbour of the current seed
[out]	is_a_seed	this value is set to true if the point with index 'nghbr' can serve as the seed

Reimplemented from pcl::RegionGrowing< PointT, NormalT >.

Definition at line 600 of file region_growing_rgb.hpp.

Member Data Documentation

template<typename PointT, typename NormalT = pcl::Normal>

float pcl::RegionGrowingRGB< PointT, NormalT >::color_p2p_threshold_ [protected]

Thershold used in color test for points.

Definition at line 252 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

float pcl::RegionGrowingRGB< PointT, NormalT >::color_r2r_threshold_ [protected]

Thershold used in color test for regions.

Definition at line 255 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

float pcl::RegionGrowingRGB< PointT, NormalT >::distance_threshold_ [protected]

Threshold that tells which points we need to assume neighbouring.

Definition at line 258 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

std::vector< std::vector<float> > pcl::RegionGrowingRGB< PointT, NormalT >::point_distances_ [protected]

Stores distances for the point neighbours from point_neighbours_.

Definition at line 264 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

unsigned int pcl::RegionGrowingRGB< PointT, NormalT >::region_neighbour_number_ [protected]

Number of neighbouring segments to find.

Definition at line 261 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

std::vector< std::vector<float> > pcl::RegionGrowingRGB< PointT, NormalT >::segment_distances_ [protected]

Stores distances for the segment neighbours from segment_neighbours_.

Definition at line 270 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

std::vector<int> pcl::RegionGrowingRGB< PointT, NormalT >::segment_labels_ [protected]

Stores new indices for segments that were obtained at the region growing stage.

Definition at line 273 of file region_growing_rgb.h.

template<typename PointT, typename NormalT = pcl::Normal>

std::vector< std::vector<int> > pcl::RegionGrowingRGB< PointT, NormalT >::segment_neighbours_ [protected]

Stores the neighboures for the corresponding segments.

Definition at line 267 of file region_growing_rgb.h.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

template<typename PointT, typename NormalT = pcl::Normal> class pcl::RegionGrowingRGB< PointT, NormalT >

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

template<typename PointT, typename NormalT = pcl::Normal>
class pcl::RegionGrowingRGB< PointT, NormalT >