cv::aruco::Dictionary Class Reference

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

#include <opencv2/objdetect/aruco_dictionary.hpp>

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.
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	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)
	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

(

)

Dictionary() [2/2]

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

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

Generate a canonical marker image.

getBitsFromByteList()

static Mat cv::aruco::Dictionary::getBitsFromByteList ( const Mat &  byteList, int  markerSize  )

static

Transform list of bytes to matrix of bits.

getByteListFromBits()

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

static

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

getDistanceToId()

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

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

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

identify()

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

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.

readDictionary()

bool cv::aruco::Dictionary::readDictionary

(

const cv::FileNode &

fn

)

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()
	)

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

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

• opencv2/objdetect/aruco_dictionary.hpp