Dictionary is a set of unique ArUco markers of the same size. More...

#include <opencv2/objdetect/aruco_dictionary.hpp>

Collaboration diagram for cv::aruco::Dictionary:

Public Member Functions
	Dictionary ()
	Dictionary (const Mat &bytesList, int _markerSize, int maxcorr=0)
	Basic ArUco dictionary constructor.
void	generateImageMarker (int id, int sidePixels, OutputArray _img, int borderBits=1) const
	Generate a canonical marker image.
int	getDistanceToId (InputArray bits, int id, bool allRotations=true) const
	Returns Hamming distance of the input bits to the specific id.
int	getDistanceToId (InputArray onlyCellPixelRatio, int id, bool allRotations, float validBitIdThreshold) const
	Returns number of cells that differ from the specific id.
Mat	getMarkerBits (int markerId, int rotationId=0) const
	Get ground truth bits float.
bool	identify (const Mat &onlyBits, int &idx, int &rotation, double maxCorrectionRate) const
	Given a matrix of bits. Returns whether if marker is identified or not.
bool	identify (const Mat &onlyCellPixelRatio, int &idx, int &rotation, double maxCorrectionRate, float validBitIdThreshold) const
	Given a matrix of pixel ratio ranging from 0 to 1. Returns whether the marker is identified or not.
bool	readDictionary (const cv::FileNode &fn)
	Read a new dictionary from FileNode.
void	writeDictionary (FileStorage &fs, const String &name=String())
	Write a dictionary to FileStorage, format is the same as in readDictionary().

Static Public Member Functions
static Mat	getBitsFromByteList (const Mat &byteList, int markerSize, int rotationId=0)
	Transform list of bytes to matrix of bits.
static Mat	getByteListFromBits (const Mat &bits)
	Transform matrix of bits to list of bytes with 4 marker rotations.

Public Attributes
Mat	bytesList
	marker code information. See class description for more details
int	markerSize
	number of bits per dimension
int	maxCorrectionBits
	maximum number of bits that can be corrected

Detailed Description

Dictionary is a set of unique ArUco markers of the same size.

bytesList storing as 2-dimensions Mat with 4-th channels (CV_8UC4 type was used) and contains the marker codewords where:

bytesList.rows is the dictionary size
each marker is encoded using nbytes = ceil(markerSize*markerSize/8.) bytes
each row contains all 4 rotations of the marker, so its length is 4*nbytes
the byte order in the bytesList[i] row: //bytes without rotation/bytes with rotation 1/bytes with rotation 2/bytes with rotation 3// So bytesList.ptr(i)[k*nbytes + j] is the j-th byte of i-th marker, in its k-th rotation.
Note
Python bindings generate matrix with shape of bytesList dictionary_size x nbytes x 4, but it should be indexed like C++ version. Python example for j-th byte of i-th marker, in its k-th rotation: aruco_dict.bytesList[id].ravel()[k*nbytes + j]

Constructor & Destructor Documentation

◆ Dictionary() [1/2]

cv::aruco::Dictionary::Dictionary ( )

Python:
	cv.aruco.Dictionary(		) ->	<aruco_Dictionary object>
	cv.aruco.Dictionary(	bytesList, _markerSize[, maxcorr]	) ->	<aruco_Dictionary object>

◆ Dictionary() [2/2]

cv::aruco::Dictionary::Dictionary	(	const Mat &	bytesList,
		int	_markerSize,
		int	maxcorr = 0 )

Python:
	cv.aruco.Dictionary(		) ->	<aruco_Dictionary object>
	cv.aruco.Dictionary(	bytesList, _markerSize[, maxcorr]	) ->	<aruco_Dictionary object>

Basic ArUco dictionary constructor.

Parameters

bytesList	bits for all ArUco markers in dictionary see memory layout in the class description
_markerSize	ArUco marker size in units
maxcorr	maximum number of bits that can be corrected

Member Function Documentation

◆ generateImageMarker()

void cv::aruco::Dictionary::generateImageMarker	(	int	id,
		int	sidePixels,
		OutputArray	_img,
		int	borderBits = 1 ) const

Python:
	cv.aruco.Dictionary.generateImageMarker(	id, sidePixels[, _img[, borderBits]]	) ->	_img

Generate a canonical marker image.

◆ getBitsFromByteList()

Mat cv::aruco::Dictionary::getBitsFromByteList	(	const Mat &	byteList,
		int	markerSize,
		int	rotationId = 0 )

static

Python:
	cv.aruco.Dictionary.getBitsFromByteList(	byteList, markerSize[, rotationId]	) ->	retval
	cv.aruco.Dictionary_getBitsFromByteList(	byteList, markerSize[, rotationId]	) ->	retval

Transform list of bytes to matrix of bits.

◆ getByteListFromBits()

Mat cv::aruco::Dictionary::getByteListFromBits ( const Mat & bits )

static

Python:
	cv.aruco.Dictionary.getByteListFromBits(	bits	) ->	retval
	cv.aruco.Dictionary_getByteListFromBits(	bits	) ->	retval

Transform matrix of bits to list of bytes with 4 marker rotations.

◆ getDistanceToId() [1/2]

int cv::aruco::Dictionary::getDistanceToId	(	InputArray	bits,
		int	id,
		bool	allRotations = true ) const

Python:
	cv.aruco.Dictionary.getDistanceToId(	bits, id[, allRotations]	) ->	retval
	cv.aruco.Dictionary.getDistanceToId(	onlyCellPixelRatio, id, allRotations, validBitIdThreshold	) ->	retval

Returns Hamming distance of the input bits to the specific id.

If allRotations flag is set, the four possible marker rotations are considered

◆ getDistanceToId() [2/2]

int cv::aruco::Dictionary::getDistanceToId	(	InputArray	onlyCellPixelRatio,
		int	id,
		bool	allRotations,
		float	validBitIdThreshold ) const

Python:
	cv.aruco.Dictionary.getDistanceToId(	bits, id[, allRotations]	) ->	retval
	cv.aruco.Dictionary.getDistanceToId(	onlyCellPixelRatio, id, allRotations, validBitIdThreshold	) ->	retval

Returns number of cells that differ from the specific id.

For each cell, the distance is increased when the difference between the detected cell pixel ratio and the dictionary bit value is greater than validBitIdThreshold. If allRotations is set, the four possible marker rotations are considered.

Parameters

onlyCellPixelRatio	markerSize x markerSize matrix (CV_32FC1) holding, for each cell, the ratio of white pixels ranging from 0 to 1
id	marker id in the dictionary to compute the distance to
allRotations	if set, the four possible marker rotations are considered and the smallest distance is returned
validBitIdThreshold	maximum allowed difference between a cell pixel ratio and the dictionary bit value; cells exceeding it are counted as differing

◆ getMarkerBits()

Mat cv::aruco::Dictionary::getMarkerBits	(	int	markerId,
		int	rotationId = 0 ) const

Python:
	cv.aruco.Dictionary.getMarkerBits(	markerId[, rotationId]	) ->	retval

Get ground truth bits float.

◆ identify() [1/2]

bool cv::aruco::Dictionary::identify	(	const Mat &	onlyBits,
		int &	idx,
		int &	rotation,
		double	maxCorrectionRate ) const

Python:
	cv.aruco.Dictionary.identify(	onlyBits, maxCorrectionRate	) ->	retval, idx, rotation
	cv.aruco.Dictionary.identify(	onlyCellPixelRatio, maxCorrectionRate, validBitIdThreshold	) ->	retval, idx, rotation

Given a matrix of bits. Returns whether if marker is identified or not.

Returns reference to the marker id in the dictionary (if any) and its rotation.

◆ identify() [2/2]

bool cv::aruco::Dictionary::identify	(	const Mat &	onlyCellPixelRatio,
		int &	idx,
		int &	rotation,
		double	maxCorrectionRate,
		float	validBitIdThreshold ) const

Python:
	cv.aruco.Dictionary.identify(	onlyBits, maxCorrectionRate	) ->	retval, idx, rotation
	cv.aruco.Dictionary.identify(	onlyCellPixelRatio, maxCorrectionRate, validBitIdThreshold	) ->	retval, idx, rotation

Given a matrix of pixel ratio ranging from 0 to 1. Returns whether the marker is identified or not.

Returns reference to the marker id in the dictionary (if any) and its rotation.

◆ readDictionary()

bool cv::aruco::Dictionary::readDictionary ( const cv::FileNode & fn )

Python:
	cv.aruco.Dictionary.readDictionary(	fn	) ->	retval

Read a new dictionary from FileNode.

Dictionary example in YAML format:
nmarkers: 35
markersize: 6
maxCorrectionBits: 5
marker_0: "101011111011111001001001101100000000"
...
marker_34: "011111010000111011111110110101100101"

◆ writeDictionary()

void cv::aruco::Dictionary::writeDictionary	(	FileStorage &	fs,
		const String &	name = String() )

Python:
	cv.aruco.Dictionary.writeDictionary(	fs[, name]	) ->	None

Write a dictionary to FileStorage, format is the same as in readDictionary().

Member Data Documentation

◆ bytesList

Mat cv::aruco::Dictionary::bytesList

marker code information. See class description for more details

◆ markerSize

int cv::aruco::Dictionary::markerSize

number of bits per dimension

◆ maxCorrectionBits

int cv::aruco::Dictionary::maxCorrectionBits

maximum number of bits that can be corrected

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

opencv2/objdetect/aruco_dictionary.hpp

Public Member Functions

Static Public Member Functions

Public Attributes