#include <RHoughTransform.hh>

Public Member Functions
Constructors, affectation, destructor
	RHoughTransform (TH2 *hptr=NULL, u_int nth=0, u_int nr=0, double rmax=0., double thr=0., const string &id="")

virtual	~RHoughTransform ()

Transform analysis options
u_int	GetOptions () const

bool	GetOptionCenterRef () const

bool	GetOptionCornerRef () const

bool	GetOptionThreshold () const

bool	GetOptionAmplWeight () const

bool	GetOptionThresholdAmplWeight () const

bool	GetOptionSmooth () const

virtual void	SetOptionCenterRef ()

virtual void	SetOptionCornerRef ()

virtual void	SetOptionAmplWeight (bool thr=false)

virtual void	SetOptionUnitWeight ()

virtual void	SetOptionSmooth ()

virtual void	SetOptionNoSmooth ()

Transform analysis functions
TH2 *	GetSourceHisto () const

const TH2 *	GetHoughHisto () const

TH2 *	GetHoughHisto ()

TH2 *	GetWeightHisto (const string &hname="") const

const TPoint &	GetSourceCenter () const

TPoint &	GetSourceCenter ()

virtual int	SetSourceHisto (TH2 *hptr, double thr=0.)

virtual void	SetThreshold (double thr)

virtual void	ResetTransform ()

virtual TH2 *	SetTransform (u_int nth, u_int nr, double rmax, const string &id="", bool calc=false)

virtual int	ComputeTransform ()

virtual double	GetWeight (double pval) const

double	GetHoughMaximum (double &theta, double &dist) const

virtual void	SuppressSourceLine (double theta, double dist, double width, u_short mode=modeCut, u_short sdiv=1)

virtual void	SetSuppressMode (u_short mode, double width)

virtual u_int	SearchLineSuppress (double hthr, u_int nlmax=1, double thtab=NULL, double rtab=NULL, double *htab=NULL, u_short sdiv=1)

ROOT related functions
virtual void	SetLineColor (Color_t c)

virtual void	SetLineWidth (Width_t w)

virtual void	SetLineStyle (Style_t s)

virtual void	SetLineAtt (TAttLine &att)

const TAttLine &	GetLineAtt () const

TAttLine &	GetLineAtt ()

TLine *	CreateLine () const

TLine *	CreateLine (double theta, double dist) const

TLine *	CreateNormal () const

TLine *	CreateNormal (double theta, double dist) const

	ClassDef (RHoughTransform, 0)

Protected Attributes
TH2 *	src_histo
	Pointer to the histogram to analyse.

TPoint	src_center
	Image histogram center.

double	threshold
	Threshold value.

TH2 *	hough_histo
	Pointer to the Hough transform histogram.

string	hough_id
	Name for the transform (histogram name)

TAttLine	line_att
	Lines draw attributes (ROOT)

u_int	options
	Transform options.

u_short	suppress_mode
	Mode for line suppression.

double	suppress_width
	Line width for suppression.

Private Member Functions
	GObject (RHoughTransform)

Static Private Attributes
static const u_int	optCenter = 0x00000001

static const u_int	optThreshold = 0x00000002

static const u_int	optAmplitude = 0x00000004

static const u_int	optSmooth = 0x00000008

static const u_short	modeCut = 0x0000

static const u_short	modeGaus = 0x0001

Detailed Description

This class performs Hough transform analysis of the image given by a 2D histogram.

The Hough transform is used to search for lines in an image.

It is supposed to work on points cloud; here, the analysis is done by weighting the contribution of each pixel with the histogram content. The X and Y dimensions of the image histogram should be in the dimension units.

The source image histogram is defined by a pointer to an histogram that is defined outside the RHoughTransform object.

Constructor & Destructor Documentation

RHoughTransform::RHoughTransform	(	TH2 *	hptr = `NULL`,
		u_int	nth = `0`,
		u_int	nr = `0`,
		double	rmax = `0.`,
		double	thr = `0.`,
		const string &	id = `""`
	)

Constructor.

Parameters

hptr	source (image) histogram
nth	number of bins of angle (0-180 deg) axis of the Hough transform
nr	number of bins of distance axis of the Hough transform
rmax	maximum distance to consider
thr	threshold for points selection
id	transform identifier (name)

RHoughTransform::~RHoughTransform ( )

virtual

Destructor.

References ResetTransform().

Member Function Documentation

RHoughTransform::GObject ( RHoughTransform )

private

Macro from GCpp library that defines the following functions:

ClassName(): return the real class name of the object
StaticClassName(): return the used class name of the object (that may be a base class of the real object).
IsInstanceOf<T>(): return true if the current object is an instance of the template class name argument
Clone(): return an allocated copy of the object.

u_int RHoughTransform::GetOptions ( ) const

inline

Return the option flags for the transform.

References options.

bool RHoughTransform::GetOptionCenterRef ( ) const

inline

Return true if the option for center reference point is set.

References optCenter, and options.

Referenced by ComputeTransform(), SetOptionCenterRef(), SetOptionCornerRef(), and SetTransform().

bool RHoughTransform::GetOptionCornerRef ( ) const

inline

Return true if the option for center reference point is not set.

References optCenter, and options.

bool RHoughTransform::GetOptionThreshold ( ) const

inline

Return true if the option for threshold validation is set.

References options, and optThreshold.

Referenced by GetWeight().

bool RHoughTransform::GetOptionAmplWeight ( ) const

inline

Return true if the option for weight from amplitude is set.

References optAmplitude, and options.

Referenced by ComputeTransform(), and GetWeight().

bool RHoughTransform::GetOptionThresholdAmplWeight ( ) const

inline

Return true if the options for weight from amplitude and threshold validation are both set.

References optAmplitude, options, and optThreshold.

bool RHoughTransform::GetOptionSmooth ( ) const

inline

Return true if the option for smoothing the Hough transform histogram is set.

References options, and optSmooth.

Referenced by ComputeTransform().

void RHoughTransform::SetOptionCenterRef ( )

virtual

Define the reference point of the analysis to be the center of the image histogram. If the transform was previously defined, it is resetted, since the analysis range in terms of distance and angles.

References GetOptionCenterRef(), optCenter, options, and ResetTransform().

void RHoughTransform::SetOptionCornerRef ( )

virtual

Define the reference point of the analysis to be the corner of the image histogram. If the transform was previously defined, it is resetted, since the analysis range in terms of distance and angles.

References GetOptionCenterRef(), optCenter, options, and ResetTransform().

void RHoughTransform::SetOptionAmplWeight ( bool thr = false )

virtual

Set the weight of image histogram bins to be the amplitude. All bins above threshold are taken into account if the threshold is defined.

Parameters

thr	indicates whether the threshold is considered

References ComputeTransform(), hough_histo, optAmplitude, options, and optThreshold.

void RHoughTransform::SetOptionUnitWeight ( )

virtual

Set the weight of image histogram bins to be 1. In this case, the threshold is automatically taken into account for bins to be taken into account.

References ComputeTransform(), hough_histo, optAmplitude, options, and optThreshold.

void RHoughTransform::SetOptionSmooth ( )

inlinevirtual

Set the option for smoothing the Hough transform histogram.

References options, and optSmooth.

void RHoughTransform::SetOptionNoSmooth ( )

inlinevirtual

Unset the option for smoothing the Hough transform histogram.

References options, and optSmooth.

TH2 * RHoughTransform::GetSourceHisto ( ) const

inline

Return the pointer to the source image histogram.

References src_histo.

const TH2 * RHoughTransform::GetHoughHisto ( ) const

inline

Return the pointer to the Hough transform histogram.

References hough_histo.

TH2 * RHoughTransform::GetHoughHisto ( )

inline

Return the pointer to the Hough transform histogram.

References hough_histo.

TH2 * RHoughTransform::GetWeightHisto ( const string & hname = "" ) const

Create an histogram from the source image histo with weight of each bin according to current options.

Parameters

hname created histogram name

References GetWeight(), and src_histo.

const TPoint & RHoughTransform::GetSourceCenter ( ) const

inline

Return the center point of the source histogram.

References src_center.

TPoint & RHoughTransform::GetSourceCenter ( )

inline

Return the center point of the source histogram.

References src_center.

int RHoughTransform::SetSourceHisto	(	TH2 *	hptr,
		double	thr = `0.`
	)

virtual

Set the source (image) histogram. If a Hough transform was previously set (with another histogram), it is recreated with the new one. The function returns 0 if no error occured.

Parameters

hptr	source (image) histogram
thr	threshold for points selection

References ComputeTransform(), hough_histo, SetThreshold(), and src_histo.

void RHoughTransform::SetThreshold ( double thr )

inlinevirtual

Set the threshold value to take a point in the analysis.

Parameters

thr	threshold value

References threshold.

Referenced by SetSourceHisto().

void RHoughTransform::ResetTransform ( )

virtual

Reset the transformation data. If created, the Hough histogram is deleted.

References hough_histo.

Referenced by SetOptionCenterRef(), SetOptionCornerRef(), SetTransform(), and ~RHoughTransform().

TH2 * RHoughTransform::SetTransform	(	u_int	nth,
		u_int	nr,
		double	rmax,
		const string &	id = `""`,
		bool	calc = `false`
	)

virtual

Function defining the Hough transform histogram. The image histogram pointer must be defined.

If the maximum distance is 0, it is taken from the image histogram diagonal.

If the transform is created successfully, the Hough transform histogram pointer is returned, otherwise a NULL pointer.

Parameters

nth	number of bins of angle (0-180 deg) axis of the Hough transform
nr	number of bins of distance axis of the Hough transform
rmax	maximum distance to consider
id	transform identifier (name)
calc	whether the Hough transform histogram is computed

References ComputeTransform(), GetOptionCenterRef(), hough_histo, hough_id, ResetTransform(), src_center, and src_histo.

int RHoughTransform::ComputeTransform ( )

virtual

Function computing the Hough transform with current parameters. The image histogram pointer must be defined.

References GetOptionAmplWeight(), GetOptionCenterRef(), GetOptionSmooth(), GetWeight(), hough_histo, src_center, and src_histo.

Referenced by SearchLineSuppress(), SetOptionAmplWeight(), SetOptionUnitWeight(), SetSourceHisto(), and SetTransform().

double RHoughTransform::GetWeight ( double pval ) const

virtual

Return the weight of a point according to the current options of the transform class.

Parameters

pval	amplitude of the point signal

References GetOptionAmplWeight(), GetOptionThreshold(), and threshold.

Referenced by ComputeTransform(), GetWeightHisto(), and SuppressSourceLine().

double RHoughTransform::GetHoughMaximum	(	double &	theta,
		double &	dist
	)		const

Return the angle and distance for the maximum value of the Hough transform histogram.

Parameters

theta	returned angle value (degree)
dist	returned distance value

References hough_histo.

Referenced by CreateLine(), CreateNormal(), and SearchLineSuppress().

void RHoughTransform::SuppressSourceLine	(	double	theta,
		double	dist,
		double	width,
		u_short	mode = `modeCut`,
		u_short	sdiv = `1`
	)

virtual

Create a copy of the source histogram, for which all the bins closer that r from the line defined by theta and dist arguments are set to 0.

Parameters

theta	line angle parameter (degree)
dist	line distance (to center) parameter
width	distance to the line of points to remove
mode	suppression mode: 0 for sharp cut 1 for gauss shape reduction cut
sdiv	histogram bins subdivision

References GetWeight(), src_center, and src_histo.

Referenced by SearchLineSuppress().

void RHoughTransform::SetSuppressMode	(	u_short	mode,
		double	width
	)

inlinevirtual

Set the configuration for line suppression in the source image for line search with suppression of lines already found.

Parameters

mode	selected suppression mode
width	line width (thickness)

References suppress_mode, and suppress_width.

u_int RHoughTransform::SearchLineSuppress	(	double	hthr,
		u_int	nlmax = `1`,
		double *	thtab = `NULL`,
		double *	rtab = `NULL`,
		double *	htab = `NULL`,
		u_short	sdiv = `1`
	)

virtual

Search for lines in the image histogram. When a line is found, it is suppressed from the image in order to search for the next line.

The function returns the number of lines found.

Be careful when setting no limit to the number of lines, since in case of problem, it may result in writing results out of the boundaries of thtab and rtab if they are defined.

Parameters

hthr	threshold in the Hough transform to accept a line detection
nlmax	maximum number of lines to search (0 for no limit)
thtab	array of resulting angles (if not NULL)
rtab	array of resulting distances (if not NULL)
htab	array of resulting Hough transform maxima (if not NULL)
sdiv	image histogram bins subdivision for line suppression

References ComputeTransform(), GetHoughMaximum(), hough_histo, src_histo, suppress_mode, suppress_width, and SuppressSourceLine().

void RHoughTransform::SetLineColor ( Color_t c )

inlinevirtual

Set the line drawing color.

Parameters

c	line color

References line_att.

void RHoughTransform::SetLineWidth ( Width_t w )

inlinevirtual

Set the line drawing width.

Parameters

w	line width

References line_att.

void RHoughTransform::SetLineStyle ( Style_t s )

inlinevirtual

Set the line drawing style.

Parameters

s	line style

References line_att.

void RHoughTransform::SetLineAtt ( TAttLine & att )

inlinevirtual

Set the line drawing attributes.

Parameters

att	line attributes

References line_att.

const TAttLine & RHoughTransform::GetLineAtt ( ) const

inline

Set the line drawing attributes.

References line_att.

TAttLine & RHoughTransform::GetLineAtt ( )

inline

Set the line drawing attributes.

References line_att.

TLine * RHoughTransform::CreateLine ( ) const

Create a line in the source histogram coordinates from current Hough transform maximum.

References GetHoughMaximum().

TLine * RHoughTransform::CreateLine	(	double	theta,
		double	dist
	)		const

Create a line in the source histogram coordinates.

Parameters

theta	angle (in degree)
dist	distance from the center

References line_att, src_center, and src_histo.

TLine * RHoughTransform::CreateNormal ( ) const

Create the normal line of a point in the Hough parameter space from current transform maximum. The line starts from the image center with a length corresponding to the distance.

References GetHoughMaximum().