icl::cv::RDPApproximation Class Reference

Ramer-Douglas-Peucker algorithm. More...

#include <RDPApproximation.h>

Classes
struct	ChainPoint

Public Member Functions
	RDPApproximation (float epsilon=0.1f, int max_corners=0, int search_iters=3)
	default constructor with given arguments More...
const std::vector< utils::Point32f > &	approximate (const std::vector< utils::Point > &poly, bool polygon=true)
	approximates a polygon More...
const std::vector< utils::Point32f > &	approximate (const std::vector< utils::Point32f > &poly, bool polygon=true)
const std::vector< utils::Point32f > &	approximate (const utils::Point *begin, const utils::Point *end, const int size, bool polygon=true)
void	drawAllPoints (core::ImgBase *img, const icl64f &value)
	draws all points to the first channel of the given image with the given value More...
const std::vector< utils::Point32f > &	getLastApproximation () const
	returns the last approximation result More...
void	setEpsilon (float value)
void	setMaxCorners (float value)
void	setSearchIterations (float value)
float	getEpsilon () const
float	getMaxCorners () const
float	getSearchIterations () const

Private Member Functions
void	approximateCurve (const ChainPoint *first, const ChainPoint *last)
	approximates a curve More...
int	approximateCurveWithCap (const ChainPoint *first, const ChainPoint *last, int cap)
	tries to approximates a curve with a maximum number of points More...
void	approximatePolygon (const ChainPoint *cps, const int size, bool polygon)
	approximates a polygon More...
void	approximateWithCap (const ChainPoint *cps, const int size, bool polygon)
	approximates a rectangle if possible More...

Private Attributes
float	epsilon
	parameters More...
int	max_corners
int	search_iters
std::vector< utils::Point32f >	approximation
	result list More...

Detailed Description

Ramer-Douglas-Peucker algorithm.

The algorithm takes an array of contour points as input. If a polygon should be approximated, then the two farthest points are found approximately. This points divide the polygon in two curves. For all curves the following is done recursively: First the perpendicular distance is calculated between each point and the line, which contains the first and last point of the curve. Afterwards the maximum distance is compared with an epsilon. The algorithm divides the curve further if the value is higher than the epsilon. Otherwise the begin and end point are taken for the result approximation. (see http://en.wikipedia.org/wiki/Ramer-Douglas-Peucker_algorithm for more information)

Parameters for the algorithm are:

• epsilon denotes the maximum ratio between the perpendicular and the line distance, that is used to filter points
• max_corners denotes the maximum number of corners; if the number of corners is higher, the algorithm return an empty list
• search_iters denotes the number of steps to find the two farthest points of a polygon

Constructor & Destructor Documentation

RDPApproximation()

icl::cv::RDPApproximation::RDPApproximation ( float  epsilon = 0.1f, int  max_corners = 0, int  search_iters = 3  )

inline

default constructor with given arguments

Member Function Documentation

approximate() [1/3]

const std::vector<utils::Point32f>& icl::cv::RDPApproximation::approximate	(	const std::vector< utils::Point > &	poly,
		bool	polygon = true
	)

approximates a polygon

the param polygon shows, if the list is a polygon or a curve

approximate() [2/3]

const std::vector<utils::Point32f>& icl::cv::RDPApproximation::approximate	(	const std::vector< utils::Point32f > &	poly,
		bool	polygon = true
	)

approximate() [3/3]

const std::vector<utils::Point32f>& icl::cv::RDPApproximation::approximate	(	const utils::Point *	begin,
		const utils::Point *	end,
		const int	size,
		bool	polygon = true
	)

approximateCurve()

void icl::cv::RDPApproximation::approximateCurve ( const ChainPoint *  first, const ChainPoint *  last  )

private

approximates a curve

approximateCurveWithCap()

int icl::cv::RDPApproximation::approximateCurveWithCap ( const ChainPoint *  first, const ChainPoint *  last, int  cap  )

private

tries to approximates a curve with a maximum number of points

the param cap shows how much points can be in between of the first and the last point

approximatePolygon()

void icl::cv::RDPApproximation::approximatePolygon ( const ChainPoint *  cps, const int  size, bool  polygon  )

private

approximates a polygon

approximateWithCap()

void icl::cv::RDPApproximation::approximateWithCap ( const ChainPoint *  cps, const int  size, bool  polygon  )

private

approximates a rectangle if possible

drawAllPoints()

void icl::cv::RDPApproximation::drawAllPoints	(	core::ImgBase *	img,
		const icl64f &	value
	)

draws all points to the first channel of the given image with the given value

getEpsilon()

float icl::cv::RDPApproximation::getEpsilon ( ) const

inline

getLastApproximation()

const std::vector<utils::Point32f>& icl::cv::RDPApproximation::getLastApproximation ( ) const

inline

returns the last approximation result

getMaxCorners()

float icl::cv::RDPApproximation::getMaxCorners ( ) const

inline

getSearchIterations()

float icl::cv::RDPApproximation::getSearchIterations ( ) const

inline

setEpsilon()

void icl::cv::RDPApproximation::setEpsilon ( float  value )

inline

setMaxCorners()

void icl::cv::RDPApproximation::setMaxCorners ( float  value )

inline

setSearchIterations()

void icl::cv::RDPApproximation::setSearchIterations ( float  value )

inline

Member Data Documentation

approximation

std::vector<utils::Point32f> icl::cv::RDPApproximation::approximation

private

result list

epsilon

float icl::cv::RDPApproximation::epsilon

private

parameters

max_corners

int icl::cv::RDPApproximation::max_corners

private

search_iters

int icl::cv::RDPApproximation::search_iters

private

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

• /Users/alneuman/vm/icl/ICLCV/src/ICLCV/RDPApproximation.h