Stereo Matching abstract class. More...

#include <pcl/stereo/stereo_matching.h>

Inheritance diagram for pcl::StereoMatching:

Public Member Functions
	StereoMatching ()

virtual	~StereoMatching ()

void	setMaxDisparity (int max_disp)
	setter for number of disparity candidates (disparity range) More...

void	setXOffset (int x_off)
	setter for horizontal offset, i.e. More...

void	setRatioFilter (int ratio_filter)
	setter for the value of the ratio filter More...

void	setPeakFilter (int peak_filter)
	setter for the value of the peak filter More...

void	setPreProcessing (bool is_pre_proc)
	setter for the pre processing step More...

void	setLeftRightCheck (bool is_lr_check)
	setter for the left-right consistency check stage, that eliminates inconsistent/wrong disparity values from the disparity map at approx. More...

void	setLeftRightCheckThreshold (int lr_check_th)
	setter for the left-right consistency check threshold More...

virtual void	compute (unsigned char ref_img, unsigned char trg_img, int width, int height)=0
	stereo processing, it computes a disparity map stored internally by the class More...

virtual void	compute (pcl::PointCloud< pcl::RGB > &ref, pcl::PointCloud< pcl::RGB > &trg)=0
	stereo processing, it computes a disparity map stored internally by the class More...

void	medianFilter (int radius)
	median filter applied on the previously computed disparity map More...

virtual bool	getPointCloud (float u_c, float v_c, float focal, float baseline, pcl::PointCloud< pcl::PointXYZ >::Ptr cloud)
	computation of the 3D point cloud from the previously computed disparity map without color information More...

virtual bool	getPointCloud (float u_c, float v_c, float focal, float baseline, pcl::PointCloud< pcl::PointXYZRGB >::Ptr cloud, pcl::PointCloud< pcl::RGB >::Ptr texture)
	computation of the 3D point cloud from the previously computed disparity map including color information More...

void	getVisualMap (pcl::PointCloud< pcl::RGB >::Ptr vMap)
	computation of a pcl::RGB cloud with scaled disparity values it can be used to display a rescaled version of the disparity map by means of the pcl::ImageViewer invalid disparity values are shown in green More...

Protected Member Functions
virtual void	preProcessing (unsigned char img, unsigned char pp_img)=0

virtual void	imgFlip (unsigned char *&img)=0

virtual void	compute_impl (unsigned char ref_img, unsigned char trg_img)=0

void	leftRightCheck ()

short int	computeStereoSubpixel (int dbest, int s1, int s2, int s3)

short int	computeStereoSubpixel (int dbest, float s1, float s2, float s3)

Protected Attributes
short int *	disp_map_
	The internal disparity map. More...

unsigned char *	ref_img_
	Local aligned copies of the cloud data. More...

unsigned char *	trg_img_

short int *	disp_map_trg_
	Disparity map used for left-right check. More...

unsigned char *	pp_ref_img_
	Local aligned copies used for pre processing. More...

unsigned char *	pp_trg_img_

int	width_
	number of pixels per column of the input stereo pair . More...

int	height_
	number of pixels per row of the input stereo pair . More...

int	max_disp_
	Disparity range used for stereo processing. More...

int	x_off_
	Horizontal displacemente (x offset) used for stereo processing. More...

int	ratio_filter_
	Threshold for the ratio filter, $\in [0 100]$ . More...

int	peak_filter_
	Threshold for the peak filter, $\in [0 \infty]$ . More...

bool	is_pre_proc_
	toggle for the activation of the pre-processing stage More...

bool	is_lr_check_
	toggle for the activation of the left-right consistency check stage More...

int	lr_check_th_
	Threshold for the left-right consistency check, typically either 0 or 1. More...

Detailed Description

Stereo Matching abstract class.

The class performs stereo matching on a rectified stereo pair.

Includes the following functionalities:

preprocessing of the image pair, to improve robustness against photometric distortions (wrt. to a spatially constant additive photometric factor)
postprocessing: filtering of wrong disparities via Peak Filter (eliminating ambiguities due to low-textured regions) and Ratio Filter (eliminating generic matching ambiguities, similar to that present in OpenCV Block Matching Stereo)
postprocessing: Left-Right consistency check (eliminates wrong disparities at the cost of twice the stereo matching computation)
postprocessing: subpixel refinement of computed disparities, to reduce the depth quantization effect
postprocessing: smoothing of the disparity map via median filter
after stereo matching a PCL point cloud can be computed, given the stereo intrinsic (focal, principal point coordinates) and extrinsic (baseline) calibration parameters

Author: Federico Tombari (feder.nosp@m.ico..nosp@m.tomba.nosp@m.ri@u.nosp@m.nibo..nosp@m.it)

Definition at line 110 of file stereo_matching.h.

Constructor & Destructor Documentation

◆ StereoMatching()

pcl::StereoMatching::StereoMatching ( )

◆ ~StereoMatching()

virtual pcl::StereoMatching::~StereoMatching ( )

virtual

Member Function Documentation

◆ compute() [1/2]

virtual void pcl::StereoMatching::compute	(	pcl::PointCloud< pcl::RGB > &	ref,
		pcl::PointCloud< pcl::RGB > &	trg
	)

pure virtual

stereo processing, it computes a disparity map stored internally by the class

Parameters

[in]	ref	point cloud of pcl::RGB type containing the pixels of the reference image (left image)
[in]	trg	point cloud of pcl::RGB type containing the pixels of the target image (right image)

Implemented in pcl::GrayStereoMatching.

◆ compute() [2/2]

virtual void pcl::StereoMatching::compute	(	unsigned char *	ref_img,
		unsigned char *	trg_img,
		int	width,
		int	height
	)

pure virtual

stereo processing, it computes a disparity map stored internally by the class

Parameters

[in]	ref_img	reference array of image pixels (left image)
[in]	trg_img	target array of image pixels (right image)
[in]	width	number of elements per row for both input arrays
[in]	height	number of elements per column for both input arrays

Implemented in pcl::GrayStereoMatching.

◆ compute_impl()

virtual void pcl::StereoMatching::compute_impl	(	unsigned char *	ref_img,
		unsigned char *	trg_img
	)

protectedpure virtual

Implemented in pcl::GrayStereoMatching.

◆ computeStereoSubpixel() [1/2]

short int pcl::StereoMatching::computeStereoSubpixel	(	int	dbest,
		float	s1,
		float	s2,
		float	s3
	)

inlineprotected

Definition at line 353 of file stereo_matching.h.

◆ computeStereoSubpixel() [2/2]

short int pcl::StereoMatching::computeStereoSubpixel	(	int	dbest,
		int	s1,
		int	s2,
		int	s3
	)

inlineprotected

Definition at line 344 of file stereo_matching.h.

◆ getPointCloud() [1/2]

virtual bool pcl::StereoMatching::getPointCloud	(	float	u_c,
		float	v_c,
		float	focal,
		float	baseline,
		pcl::PointCloud< pcl::PointXYZ >::Ptr	cloud
	)

virtual

computation of the 3D point cloud from the previously computed disparity map without color information

Note: The "compute" method must have been previously called at least once in order for this function to have any effect

Parameters

[in]	u_c	horizontal coordinate of the principal point (calibration parameter)
[in]	v_c	vertical coordinate of the principal point (calibration parameter)
[in]	focal	focal length in pixels (calibration parameter)
[in]	baseline	distance between the two cameras (calibration parameter); the measure unit used to specify this parameter will be the same as the 3D points in the output point cloud
[out]	cloud	output 3D point cloud; it is organized and non-dense, with NaNs where 3D points are invalid

◆ getPointCloud() [2/2]

virtual bool pcl::StereoMatching::getPointCloud	(	float	u_c,
		float	v_c,
		float	focal,
		float	baseline,
		pcl::PointCloud< pcl::PointXYZRGB >::Ptr	cloud,
		pcl::PointCloud< pcl::RGB >::Ptr	texture
	)

virtual

computation of the 3D point cloud from the previously computed disparity map including color information

Note: The "compute" method must have been previously called at least once in order for this function to have any effect

Parameters

[in]	u_c	horizontal coordinate of the principal point (calibration parameter)
[in]	v_c	vertical coordinate of the principal point (calibration parameter)
[in]	focal	focal length in pixels (calibration parameter)
[in]	baseline	distance between the two cameras (calibration parameter); the measure unit used to specify this parameter will be the same as the 3D points in the output point cloud
[out]	cloud	output 3D point cloud; it is organized and non-dense, with NaNs where 3D points are invalid
[in]	texture	3D cloud (same size of the output cloud) used to associate to each 3D point of the output cloud a color triplet

◆ getVisualMap()

void pcl::StereoMatching::getVisualMap ( pcl::PointCloud< pcl::RGB >::Ptr vMap )

computation of a pcl::RGB cloud with scaled disparity values it can be used to display a rescaled version of the disparity map by means of the pcl::ImageViewer invalid disparity values are shown in green

Note: The "compute" method must have been previously called at least once in order for this function to have any effect

Parameters

[out] vMap output cloud

◆ imgFlip()

virtual void pcl::StereoMatching::imgFlip ( unsigned char *& img )

protectedpure virtual

Implemented in pcl::GrayStereoMatching.

◆ leftRightCheck()

void pcl::StereoMatching::leftRightCheck ( )

protected

◆ medianFilter()

void pcl::StereoMatching::medianFilter ( int radius )

median filter applied on the previously computed disparity map

Note: The "compute" method must have been previously called at least once in order for this function to have any effect

Parameters

[in] radius radius of the squared window used to compute the median filter; the window side is equal to 2*radius + 1

◆ preProcessing()

virtual void pcl::StereoMatching::preProcessing	(	unsigned char *	img,
		unsigned char *	pp_img
	)

protectedpure virtual

Implemented in pcl::GrayStereoMatching.

◆ setLeftRightCheck()

void pcl::StereoMatching::setLeftRightCheck ( bool is_lr_check )

inline

setter for the left-right consistency check stage, that eliminates inconsistent/wrong disparity values from the disparity map at approx.

twice the processing cost of the selected stereo algorithm

Parameters

[in] is_lr_check setting the boolean to true activates the left-right consistency check

Definition at line 179 of file stereo_matching.h.

◆ setLeftRightCheckThreshold()

void pcl::StereoMatching::setLeftRightCheckThreshold ( int lr_check_th )

inline

setter for the left-right consistency check threshold

Parameters

[in] lr_check_th sets the value of the left-right consistency check threshold only has some influence if the left-right check is active typically has either the value 0 ("strong" consistency check, more points being filtered) or 1 ("weak" consistency check, less points being filtered)

Definition at line 192 of file stereo_matching.h.

◆ setMaxDisparity()

void pcl::StereoMatching::setMaxDisparity ( int max_disp )

inline

setter for number of disparity candidates (disparity range)

Parameters

[in] max_disp number of disparity candidates (disparity range); has to be > 0

Definition at line 121 of file stereo_matching.h.

◆ setPeakFilter()

void pcl::StereoMatching::setPeakFilter ( int peak_filter )

inline

setter for the value of the peak filter

Parameters

[in] peak_filter value of the peak filter; it is a number in the range [0, inf] (0: no filtering action)

Definition at line 155 of file stereo_matching.h.

◆ setPreProcessing()

void pcl::StereoMatching::setPreProcessing ( bool is_pre_proc )

inline

setter for the pre processing step

Parameters

[in] is_pre_proc setting the boolean to true activates the pre-processing step for both stereo images

Definition at line 166 of file stereo_matching.h.

◆ setRatioFilter()

void pcl::StereoMatching::setRatioFilter ( int ratio_filter )

inline

setter for the value of the ratio filter

Parameters

[in] ratio_filter value of the ratio filter; it is a number in the range [0, 100] (0: no filtering action; 100: all disparities are filtered)

Definition at line 144 of file stereo_matching.h.

◆ setXOffset()

void pcl::StereoMatching::setXOffset ( int x_off )

inline

setter for horizontal offset, i.e.

number of pixels to shift the disparity range over the target image

Parameters

[in] x_off horizontal offset value; has to be >= 0

Definition at line 132 of file stereo_matching.h.

Member Data Documentation

◆ disp_map_

short int* pcl::StereoMatching::disp_map_

protected

The internal disparity map.

Definition at line 291 of file stereo_matching.h.

◆ disp_map_trg_

short int* pcl::StereoMatching::disp_map_trg_

protected

Disparity map used for left-right check.

Definition at line 298 of file stereo_matching.h.

◆ height_

int pcl::StereoMatching::height_

protected

number of pixels per row of the input stereo pair .

Definition at line 308 of file stereo_matching.h.

◆ is_lr_check_

bool pcl::StereoMatching::is_lr_check_

protected

toggle for the activation of the left-right consistency check stage

Definition at line 326 of file stereo_matching.h.

◆ is_pre_proc_

bool pcl::StereoMatching::is_pre_proc_

protected

toggle for the activation of the pre-processing stage

Definition at line 323 of file stereo_matching.h.

◆ lr_check_th_

int pcl::StereoMatching::lr_check_th_

protected

Threshold for the left-right consistency check, typically either 0 or 1.

Definition at line 329 of file stereo_matching.h.

◆ max_disp_

int pcl::StereoMatching::max_disp_

protected

Disparity range used for stereo processing.

Definition at line 311 of file stereo_matching.h.

◆ peak_filter_

int pcl::StereoMatching::peak_filter_

protected

Threshold for the peak filter, $\in [0 \infty]$ .

Definition at line 320 of file stereo_matching.h.

◆ pp_ref_img_

unsigned char* pcl::StereoMatching::pp_ref_img_

protected

Local aligned copies used for pre processing.

Definition at line 301 of file stereo_matching.h.

◆ pp_trg_img_

unsigned char* pcl::StereoMatching::pp_trg_img_

protected

Definition at line 302 of file stereo_matching.h.

◆ ratio_filter_

int pcl::StereoMatching::ratio_filter_

protected

Threshold for the ratio filter, $\in [0 100]$ .

Definition at line 317 of file stereo_matching.h.

◆ ref_img_

unsigned char* pcl::StereoMatching::ref_img_

protected

Local aligned copies of the cloud data.

Definition at line 294 of file stereo_matching.h.

◆ trg_img_

unsigned char* pcl::StereoMatching::trg_img_

protected

Definition at line 295 of file stereo_matching.h.

◆ width_

int pcl::StereoMatching::width_

protected

number of pixels per column of the input stereo pair .

Definition at line 305 of file stereo_matching.h.

◆ x_off_

int pcl::StereoMatching::x_off_

protected

Horizontal displacemente (x offset) used for stereo processing.

Definition at line 314 of file stereo_matching.h.

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

pcl/stereo/stereo_matching.h

Public Member Functions

Protected Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ StereoMatching()

◆ ~StereoMatching()

Member Function Documentation

◆ compute() [1/2]

◆ compute() [2/2]

◆ compute_impl()

◆ computeStereoSubpixel() [1/2]

◆ computeStereoSubpixel() [2/2]

◆ getPointCloud() [1/2]

◆ getPointCloud() [2/2]

◆ getVisualMap()

◆ imgFlip()

◆ leftRightCheck()

◆ medianFilter()

◆ preProcessing()

◆ setLeftRightCheck()

◆ setLeftRightCheckThreshold()

◆ setMaxDisparity()

◆ setPeakFilter()

◆ setPreProcessing()

◆ setRatioFilter()

◆ setXOffset()

Member Data Documentation

◆ disp_map_

◆ disp_map_trg_

◆ height_

◆ is_lr_check_

◆ is_pre_proc_

◆ lr_check_th_

◆ max_disp_

◆ peak_filter_

◆ pp_ref_img_

◆ pp_trg_img_

◆ ratio_filter_

◆ ref_img_

◆ trg_img_

◆ width_

◆ x_off_