Curvature Corner Detector. More...

#include <CornerDetectorCSS.h>

Inheritance diagram for icl::cv::CornerDetectorCSS:

Classes
struct	GaussianKernel
	1 dim gaussian kernel More...

Public Member Functions
	CornerDetectorCSS (float angle_thresh=162., float rc_coeff=1.5, float sigma=3., float curvature_cutoff=100., float straight_line_thresh=0.1, bool accurate=false)
	Default constructor with given arguments. More...

	~CornerDetectorCSS ()
	Destructor. More...

virtual void	setPropertyValue (const std::string &propertyName, const utils::Any &value)
	sets value of a property (always call call_callbacks(propertyName) or Configurable::setPropertyValue) More...

virtual std::vector< std::string >	getPropertyList () const
	returns Configurable property list More...

virtual std::string	getPropertyType (const std::string &propertyName) const
	returns type of given property More...

virtual std::string	getPropertyInfo (const std::string &propertyName) const
	returns info for given property More...

virtual utils::Any	getPropertyValue (const std::string &propertyName) const
	returns value for given property More...

virtual int	getPropertyVolatileness (const std::string &propertyName) const
	returns volatileness for given property More...

virtual std::string	getPropertyToolTip (const std::string &propertyName) const
	returns property descriptions More...

template<class T >
ICLCV_API const std::vector< std::vector< utils::Point32f > > &	detectCorners (const std::vector< std::vector< T > > &boundaries, const std::vector< icl32f > &sigmas)
	detects the corners in the passed contour More...

template<class T >
ICLCV_API const std::vector< utils::Point32f > &	detectCorners (const std::vector< T > &boundary)

const std::vector< utils::Point32f > &	getLastCorners () const
	returns the result of last detectCorners call More...

void	setAngleThreshold (float value)

void	setRCCoeff (float value)

void	setSigma (float value)

void	setCurvatureCutoff (float value)

void	setStraightLineThreshold (float value)

void	setAccurate (bool value)

float	getAngleThreshold () const

float	getRCCoeff () const

float	getSigma () const

float	getCurvatureCutoff () const

float	getStraightLineThreshold () const

bool	getAccurate () const

Public Member Functions inherited from icl::utils::Configurable
virtual	~Configurable ()
	virtual destructor More...

	Configurable (const Configurable &other)
	Copy constructor. More...

Configurable &	operator= (const Configurable &other)
	Assignment operator. More...

void	setConfigurableID (const std::string &ID)
	sets the ID of this configurable More...

const std::string &	getConfigurableID () const
	returns the configurables static ID More...

bool	isOrderedFlagSet () const
	returns whether the ordered flag is set More...

void	deactivateProperty (const std::string &pattern)
	adds an additional deativation pattern More...

void	deleteDeactivationPattern (const std::string &pattern)
	removed a formerly added deactivation pattern More...

std::vector< std::string >	getPropertyListWithoutDeactivated () const
	this returns a filtered list of properties (using all filters added by deactivateProperty) More...

virtual void	adaptProperty (const std::string &name, const std::string &newType, const std::string &newInfo, const std::string &newToolTip)
	this function can be used to adapt a specific property afterwards More...

void	registerCallback (const Callback &cb)
	add a callback for changed properties More...

void	removedCallback (const Callback &cb)
	removes a callback that was registered before More...

void	syncChangesTo (Configurable *others, int num=1)
	this can be used to let this instance also apply property changes to others More...

virtual bool	supportsProperty (const std::string &propertyName) const
	base implementation for property check (seaches in the property list) More...

virtual void	saveProperties (const std::string &filename, const std::vector< std::string > &propertiesToSkip=EMPTY_VEC) const
	writes all available properties into a file More...

virtual void	loadProperties (const std::string &filename, const std::vector< std::string > &propertiesToSkip=EMPTY_VEC)
	reads a camera config file from disc More...

Static Public Member Functions
static int	gaussian (GaussianKernel &gauss, float sigma, float cutoff)
	calculates a normalized 1d gaussian std::vector More...

static void	convolute_1D (float vec, int dim, float kernel, int kernelDim, float *dst)
	Small wrapper for ippsConv_32f. More...

Static Public Member Functions inherited from icl::utils::Configurable
static std::string	create_default_ID (const std::string &prefix)
	this function can be used in subclasses to create a default ID More...

static Configurable *	get (const std::string &id)
	returns configurable by given ID More...

static void	register_configurable_type (const std::string &classname, Function< Configurable * > creator)
	registers a configurable type More...

static std::vector< std::string >	get_registered_configurables ()
	returns a list of all registered configurable classnames More...

static Configurable *	create_configurable (const std::string &classname)
	creates a configurable by given name More...

Private Member Functions
int	gauss_radius (float sigma, float cutoff)

void	fill_gauss (float *mask, float sigma, int width)

void	convolute (const float data, int data_length, const float mask, int mask_length, float *convoluted)

void	calculate_curvatures (const float smoothed_x, const float smoothed_y, int length, float curvature_cutoff, float *curvatures)

void	calculate_curvatures_bulk (int array_length, int num_boundaries, const int lengths, const int indices, const int indices_padded, const float smoothed_x, const float smoothed_y, float curvature_cutoff, float curvature)

int	findExtrema (int extrema, int num_extrema_out, float *k, int length)

void	removeRoundCorners (float rc_coeff, int maxima_offset, float k, int length, int extrema, int num_extrema, int new_extrema, int num_new_extrema_out)

void	removeRoundCornersAccurate (float rc_coeff, int maxima_offset, float k, int length, int extrema, int num_extrema, int extrema_out, int num_extrema_out)

float	cornerAngle (float x, float y, int prev, int current, int next, int length, float straight_line_thresh)

float	cornerAngleAccurate (float x, float y, int prev, int current, int next, int array_length, float straight_line_thresh)

void	removeFalseCorners (float angle_thresh, float x, float y, float k, int length, int maxima, int num_maxima, int maxima_out, int num_maxima_out)

Private Attributes
float	angle_thresh
	parameters More...

float	rc_coeff

float	sigma

float	curvature_cutoff

float	straight_line_thresh

bool	accurate
	use acurate corner detection More...

std::vector< utils::Point32f >	corners

std::vector< std::vector< utils::Point32f > >	corners_list

CLCurvature *	clcurvature

bool	useOpenCL

Additional Inherited Members
Public Types inherited from icl::utils::Configurable
typedef Function< void, const Property & >	Callback
	Function type for changed properties. More...

Static Public Attributes inherited from icl::utils::Configurable
static const std::vector< std::string >	EMPTY_VEC
	used as shortcut – just an empty vector of std::strings More...

Protected Member Functions inherited from icl::utils::Configurable
void	addProperty (const std::string &name, const std::string &type, const std::string &info, const Any &value=Any(), const int volatileness=0, const std::string &tooltip=std::string())
	This can be used by derived classes to store supported properties in the internal list. More...

void	addChildConfigurable (Configurable *configurable, const std::string &childPrefix="")
	This adds another configurable as child. More...

void	removeChildConfigurable (Configurable *configurable)
	removes the given child configurable More...

Property &	prop (const std::string &propertyName)
	this CAN be used e.g. to store a property value in internal property-list More...

const Property &	prop (const std::string &propertyName) const
	this CAN be used e.g. to store a property value in internal property-list More...

	Configurable (const std::string &ID="", bool ordered=true)
	create this configurable with given ID More...

void	call_callbacks (const std::string &propertyName, const Configurable *caller) const
	calls all registered callbacks More...

Protected Member Functions inherited from icl::utils::Uncopyable
	Uncopyable ()
	Empty base constructor. More...

Protected Attributes inherited from icl::utils::Configurable
std::vector< Callback >	callbacks
	internally managed list of callbacks More...

Detailed Description

Curvature Corner Detector.

Implementation of the Curvature Scale Space corner detection algorithm described in the paper "Corner detector based on global and local curvature properties", by Chen He, Xiao and Yung, Nelson H.C. in Optical Engineering 2008. There also is a Matlab implementation of the algorithm by Chen He, Xiao available at http://www.mathworks.com/matlabcentral/fileexchange/7652

The algorithm takes an array of contour points as input, that are then smoothed by a gaussian filter. Afterwards the curvature function is calculated and its maxima positions are taken as corner candidates. Afterwards all candidates which belong to round or "false" (noise induced, etc.) corners are removed and finally a list of corners is given back.

Parameters for the algorithm are:

rc_coeff denotes the minimum ratio of major axis to minor axis of an ellipse, whose vertex could be detected as a corner by proposed detector The default value is 1.5.
angle_thresh denotes the maximum obtuse angle that a corner can have when it is detected as a true corner, default value is 162.
sigma denotes the standard deviation of the Gaussian filter when computeing curvature. The default sig is 3.
straight_line_thresh to estimate the angle of a corner, either a circle or a straight line approximation of the left and right surrounding is used. The straight line approximation is used, if the angle between the left neigbour, corner candidate and and the point on the contour half way between them is smaller than straight_line_thresh. 0 leads to circle approximation only, 180 to straight line approximation only.

Diffent to the reference implementation of Xiao He, the second half of the contour is copied before the start of the contour and the first half of the contour is copied behind the end of the contour. That way, the (artificially) first and last corners in the closed contour are calculated more acurately, since there are no discontinuities.

usage example:
const std::vector<icl::Region> &rs = d.detect(&image);
const std::vector<Point32f> &boundary = getThinnedBoundary(rs[0].getBoundary());
CornerDetectorCSS css;
const std::vector<Point32f> &corners = css.detectCorners(boundary);

Constructor & Destructor Documentation

◆ CornerDetectorCSS()

icl::cv::CornerDetectorCSS::CornerDetectorCSS	(	float	angle_thresh = `162.`,
		float	rc_coeff = `1.5`,
		float	sigma = `3.`,
		float	curvature_cutoff = `100.`,
		float	straight_line_thresh = `0.1`,
		bool	accurate = `false`
	)

Default constructor with given arguments.

◆ ~CornerDetectorCSS()

icl::cv::CornerDetectorCSS::~CornerDetectorCSS ( )

Destructor.

Member Function Documentation

◆ calculate_curvatures()

void icl::cv::CornerDetectorCSS::calculate_curvatures	(	const float *	smoothed_x,
		const float *	smoothed_y,
		int	length,
		float	curvature_cutoff,
		float *	curvatures
	)

private

◆ calculate_curvatures_bulk()

void icl::cv::CornerDetectorCSS::calculate_curvatures_bulk	(	int	array_length,
		int	num_boundaries,
		const int *	lengths,
		const int *	indices,
		const int *	indices_padded,
		const float *	smoothed_x,
		const float *	smoothed_y,
		float	curvature_cutoff,
		float *	curvature
	)

private

◆ convolute()

void icl::cv::CornerDetectorCSS::convolute	(	const float *	data,
		int	data_length,
		const float *	mask,
		int	mask_length,
		float *	convoluted
	)

private

◆ convolute_1D()

static void icl::cv::CornerDetectorCSS::convolute_1D	(	float *	vec,
		int	dim,
		float *	kernel,
		int	kernelDim,
		float *	dst
	)

static

Small wrapper for ippsConv_32f.

Parameters

vec
dim
kernel
kernelDim
dst	destination data pointer of size dim+kernelDim -1 Performs the following operation \f[ \mbox{dst}[n] = \sum\limits_{k=0}^n \mbox{src}[k] \cdot \mbox{kernel}[n-k] \f] for all \f$ n \in [0,\mbox{dim}+\mbox{kernelDim}-1]\f$ with \f$ \mbox{src}[x] = 0 \f$ for \f$ x \not\in [0,\mbox{dim}-1] \f$ and \f$ \mbox{kernel}[x] = 0\f$ for \f$ x \not\in [0,\mbox{kernelDim}-1] \f$

◆ cornerAngle()

float icl::cv::CornerDetectorCSS::cornerAngle	(	float *	x,
		float *	y,
		int	prev,
		int	current,
		int	next,
		int	length,
		float	straight_line_thresh
	)

private

◆ cornerAngleAccurate()

float icl::cv::CornerDetectorCSS::cornerAngleAccurate	(	float *	x,
		float *	y,
		int	prev,
		int	current,
		int	next,
		int	array_length,
		float	straight_line_thresh
	)

private

◆ detectCorners() [1/2]

template<class T >

ICLCV_API const std::vector<std::vector<utils::Point32f> >& icl::cv::CornerDetectorCSS::detectCorners	(	const std::vector< std::vector< T > > &	boundaries,
		const std::vector< icl32f > &	sigmas
	)

detects the corners in the passed contour

Use this function to detect the corners in an image.
A reference to the contour in which the corners should be detected must be passed. The contour should be "thinned", meaning that it should look e.g. like

ooox                ooxx
ooxo  and not like  oxxo
oxoo                xxoo
xooo                xooo

◆ detectCorners() [2/2]

template<class T >

ICLCV_API const std::vector<utils::Point32f>& icl::cv::CornerDetectorCSS::detectCorners ( const std::vector< T > & boundary )

◆ fill_gauss()

void icl::cv::CornerDetectorCSS::fill_gauss	(	float *	mask,
		float	sigma,
		int	width
	)

private

◆ findExtrema()

int icl::cv::CornerDetectorCSS::findExtrema	(	int *	extrema,
		int *	num_extrema_out,
		float *	k,
		int	length
	)

private

◆ gauss_radius()

int icl::cv::CornerDetectorCSS::gauss_radius	(	float	sigma,
		float	cutoff
	)

private

◆ gaussian()

static int icl::cv::CornerDetectorCSS::gaussian	(	GaussianKernel &	gauss,
		float	sigma,
		float	cutoff
	)

static

calculates a normalized 1d gaussian std::vector

Parameters

gauss	reference to GaussianKernel struct
sigma	sigma^2 is the variance of the gaussian, default is 1
cutoff	if value of gaussian drops below this value, it is set to zero, default is 0.001

Returns: width of the gaussian tails, so the size of the returned std::vector is 2*width+1

◆ getAccurate()

bool icl::cv::CornerDetectorCSS::getAccurate ( ) const

inline

◆ getAngleThreshold()

float icl::cv::CornerDetectorCSS::getAngleThreshold ( ) const

inline

◆ getCurvatureCutoff()

float icl::cv::CornerDetectorCSS::getCurvatureCutoff ( ) const

inline

◆ getLastCorners()

const std::vector<utils::Point32f>& icl::cv::CornerDetectorCSS::getLastCorners ( ) const

inline

returns the result of last detectCorners call

This function can be used as optimization e.g. whithin ICLCV::Region implementation

◆ getPropertyInfo()

virtual std::string icl::cv::CornerDetectorCSS::getPropertyInfo ( const std::string & propertyName ) const

virtual

returns info for given property

Reimplemented from icl::utils::Configurable.

◆ getPropertyList()

virtual std::vector<std::string> icl::cv::CornerDetectorCSS::getPropertyList ( ) const

virtual

returns Configurable property list

Reimplemented from icl::utils::Configurable.

◆ getPropertyToolTip()

virtual std::string icl::cv::CornerDetectorCSS::getPropertyToolTip ( const std::string & propertyName ) const

virtual

returns property descriptions

Reimplemented from icl::utils::Configurable.

◆ getPropertyType()

virtual std::string icl::cv::CornerDetectorCSS::getPropertyType ( const std::string & propertyName ) const

virtual

returns type of given property

Reimplemented from icl::utils::Configurable.

◆ getPropertyValue()

virtual utils::Any icl::cv::CornerDetectorCSS::getPropertyValue ( const std::string & propertyName ) const

virtual

returns value for given property

Reimplemented from icl::utils::Configurable.

◆ getPropertyVolatileness()

virtual int icl::cv::CornerDetectorCSS::getPropertyVolatileness ( const std::string & propertyName ) const

inlinevirtual

returns volatileness for given property

Reimplemented from icl::utils::Configurable.

◆ getRCCoeff()

float icl::cv::CornerDetectorCSS::getRCCoeff ( ) const

inline

◆ getSigma()

float icl::cv::CornerDetectorCSS::getSigma ( ) const

inline

◆ getStraightLineThreshold()

float icl::cv::CornerDetectorCSS::getStraightLineThreshold ( ) const

inline

◆ removeFalseCorners()

void icl::cv::CornerDetectorCSS::removeFalseCorners	(	float	angle_thresh,
		float *	x,
		float *	y,
		float *	k,
		int	length,
		int *	maxima,
		int	num_maxima,
		int *	maxima_out,
		int *	num_maxima_out
	)

private

◆ removeRoundCorners()

void icl::cv::CornerDetectorCSS::removeRoundCorners	(	float	rc_coeff,
		int	maxima_offset,
		float *	k,
		int	length,
		int *	extrema,
		int	num_extrema,
		int *	new_extrema,
		int *	num_new_extrema_out
	)

private

◆ removeRoundCornersAccurate()

void icl::cv::CornerDetectorCSS::removeRoundCornersAccurate	(	float	rc_coeff,
		int	maxima_offset,
		float *	k,
		int	length,
		int *	extrema,
		int	num_extrema,
		int *	extrema_out,
		int *	num_extrema_out
	)

private

◆ setAccurate()

void icl::cv::CornerDetectorCSS::setAccurate ( bool value )

inline

◆ setAngleThreshold()

void icl::cv::CornerDetectorCSS::setAngleThreshold ( float value )

inline

◆ setCurvatureCutoff()

void icl::cv::CornerDetectorCSS::setCurvatureCutoff ( float value )

inline

◆ setPropertyValue()

virtual void icl::cv::CornerDetectorCSS::setPropertyValue	(	const std::string &	propertyName,
		const utils::Any &	value
	)

virtual

sets value of a property (always call call_callbacks(propertyName) or Configurable::setPropertyValue)

Reimplemented from icl::utils::Configurable.

◆ setRCCoeff()

void icl::cv::CornerDetectorCSS::setRCCoeff ( float value )

inline

◆ setSigma()

void icl::cv::CornerDetectorCSS::setSigma ( float value )

inline

◆ setStraightLineThreshold()

void icl::cv::CornerDetectorCSS::setStraightLineThreshold ( float value )

inline

Member Data Documentation

◆ accurate

bool icl::cv::CornerDetectorCSS::accurate

private

use acurate corner detection

◆ angle_thresh

float icl::cv::CornerDetectorCSS::angle_thresh

private

parameters

◆ clcurvature

CLCurvature* icl::cv::CornerDetectorCSS::clcurvature

private

◆ corners

std::vector<utils::Point32f> icl::cv::CornerDetectorCSS::corners

private

◆ corners_list

std::vector<std::vector<utils::Point32f> > icl::cv::CornerDetectorCSS::corners_list

private

◆ curvature_cutoff

float icl::cv::CornerDetectorCSS::curvature_cutoff

private

◆ rc_coeff

float icl::cv::CornerDetectorCSS::rc_coeff

private

◆ sigma

float icl::cv::CornerDetectorCSS::sigma

private

◆ straight_line_thresh

float icl::cv::CornerDetectorCSS::straight_line_thresh

private

◆ useOpenCL

bool icl::cv::CornerDetectorCSS::useOpenCL

private

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

/Users/alneuman/vm/icl/ICLCV/src/ICLCV/CornerDetectorCSS.h

Classes

Public Member Functions

Static Public Member Functions

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ CornerDetectorCSS()

◆ ~CornerDetectorCSS()

Member Function Documentation

◆ calculate_curvatures()

◆ calculate_curvatures_bulk()

◆ convolute()

◆ convolute_1D()

◆ cornerAngle()

◆ cornerAngleAccurate()

◆ detectCorners() [1/2]

◆ detectCorners() [2/2]

◆ fill_gauss()

◆ findExtrema()

◆ gauss_radius()

◆ gaussian()

◆ getAccurate()

◆ getAngleThreshold()

◆ getCurvatureCutoff()

◆ getLastCorners()

◆ getPropertyInfo()

◆ getPropertyList()

◆ getPropertyToolTip()

◆ getPropertyType()

◆ getPropertyValue()

◆ getPropertyVolatileness()

◆ getRCCoeff()

◆ getSigma()

◆ getStraightLineThreshold()

◆ removeFalseCorners()

◆ removeRoundCorners()

◆ removeRoundCornersAccurate()

◆ setAccurate()

◆ setAngleThreshold()

◆ setCurvatureCutoff()

◆ setPropertyValue()

◆ setRCCoeff()

◆ setSigma()

◆ setStraightLineThreshold()

Member Data Documentation

◆ accurate

◆ angle_thresh

◆ clcurvature

◆ corners

◆ corners_list

◆ curvature_cutoff

◆ rc_coeff

◆ sigma

◆ straight_line_thresh

◆ useOpenCL