cv::aruco::Dictionary Class Reference

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

#include <aruco_dictionary.hpp>

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

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

Public Attributes
CV_PROP_RW Mat	bytesList
	marker code information. See class description for more details
CV_PROP_RW int	markerSize
	number of bits per dimension
CV_PROP_RW 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_WRAP cv::aruco::Dictionary::Dictionary

(

)

Dictionary() [2/2]

CV_WRAP 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()

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

Generate a canonical marker image.

getBitsFromByteList()

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

static

Transform list of bytes to matrix of bits.

getByteListFromBits()

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

static

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

getDistanceToId()

CV_WRAP 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()

CV_WRAP bool cv::aruco::Dictionary::identify	(	const Mat &	onlyBits,
		CV_OUT int &	idx,
		CV_OUT 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()

CV_WRAP 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()

CV_WRAP 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

CV_PROP_RW Mat cv::aruco::Dictionary::bytesList

marker code information. See class description for more details

markerSize

CV_PROP_RW int cv::aruco::Dictionary::markerSize

number of bits per dimension

maxCorrectionBits

CV_PROP_RW 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:

• build/release/_deps/opencv-src/include/opencv4/opencv2/objdetect/aruco_dictionary.hpp