Module Documentation

Detect and decode 3 kinds of coded patterns which can be useful to a robot:

The three algorithms run in parallel. You should be able to sustain 50 frames/s at 320x240 camera resolution, and 20 frames/s at 640x480 camera resolution.

Serial Messages

This module can send standardized serial messages as described in Standardized serial messages formatting.

When dopose is turned on, 3D messages will be sent, otherwise 2D messages.

One message is issued for every detected marker, on every video frame.

2D messages when msg3d and dopose are off:

Serial message type: 2D
id: decoded marker ID (with prefix 'U' for ArUco, or 'A' for ARtoolkit), or type of symbol (e.g., QR-Code, ISBN13, etc).
x, y, or vertices: standardized 2D coordinates of marker center or corners
w, h: standardized marker size
extra: none (empty string) for ArUco and ARtoolkit markers, otherwise decoded barcode or QRcode content.

3D messages when msg3d and dopose are on:

Serial message type: 3D
id: decoded marker ID (with prefix 'U' for ArUco, or 'A' for ARtoolkit), or type of symbol (e.g., QR-Code, ISBN13, etc).
x, y, z, or vertices: 3D coordinates in millimeters of marker center or corners
w, h, d: marker size in millimeters, a depth of 1mm is always used
extra: none (empty string) for ArUco and ARtoolkit markers, otherwise decoded barcode or QRcode content.

If you will use the quaternion data (Detail message style; see Standardized serial messages formatting), you should probably set the serprec parameter to something non-zero to get enough accuracy in the quaternion values.

See Standardized serial messages formatting for more on standardized serial messages, and Helper functions to convert coordinates from camera resolution to standardized for more info on standardized coordinates.

Parameter

Type

Description

Default

Valid Values

(ARtoolkit) camparams

std::string

File stem of camera parameters, or empty. Camera resolution will be appended, as well as a .dat extension. For example, specifying 'camera_para' here and running the camera sensor at 320x240 will attempt to load camera_para320x240.dat from within the module's directory (if relative stem) or from the specified absolute location (if absolute stem).

JEVOIS_SHARE_PATH /camera/camera_para

(ARtoolkit) contpose

bool

Use continuous pose estimation in good quality video

true

(ARtoolkit) msg3d

bool

Send 3D serial messages if true, otherwise 2D

false

(ARtoolkit) threshmode

DictThreshMode

Dictionary threshold mode to use, affects robustness to varying lighting conditions

DictThreshMode::AR_LABELING_THRESH_MODE_AUTO_OTSU

DictThreshMode_Values

(ARtoolkit) dictionary

Dict

Symbol dictionary to use

Dict::AR_MATRIX_CODE_3x3_PARITY65

Dict_Values

(ARtoolkit) confthresh

double

Minimum confidence threshold required for valid detections

0.7

jevois::Range<double>(0.0, 1.0)

(ArUco) camparams

std::string

File stem of camera parameters, or empty. Camera resolution will be appended, as well as a .yaml extension. For example, specifying 'calibration' here and running the camera sensor at 320x240 will attempt to load calibration320x240.yaml from within directory JEVOIS_SHARE_PATH /camera/ - Note that this parameter cannot be changed at runtime (must be set in the module's params.cfg).

calibration

(ArUco) detparams

std::string

Filename of detector parameters, or empty - Note that this parameter cannot be changed at runtime (must be set in the module's params.cfg).

(ArUco) dictionary

Dict

Symbol dictionary to use - Note that this parameter cannot be changed at runtime (must be set in the module's params.cfg).

Dict::D4X4_50

Dict_Values

(ArUco) dopose

bool

Compute (and show) pose vectors, requires a valid camera calibration

false

(ArUco) markerlen

float

Marker side length (millimeters), used only for pose estimation

100.0F

(ArUco) showcube

bool

Show a 3D cube on top of each detected marker, when dopose is also true

false

(QRcode) symbol

std::string

Type(s) of QR code / barcode symbols searched for, multiple entries are possible and should be separated by / characters. Selecting many symbol types or ALL will slow down processing. Supported symbols are: QRCODE, EAN2, EAN5, EAN8, EAN13, UPCE, UPCA, ISBN10, ISBN13, COMPOSITE, I25, DATABAR, DATABAREXP, CODABAR, CODE39, PDF417, CODE93, and CODE128

ALL

(QRcode) xdensity

int

Scanner vertical scan density (pixel stride), or 0 to disable

(QRcode) ydensity

int

Scanner horizontal scan density (pixel stride), or 0 to disable

Detailed docs:

MarkersCombo

License:

GPL v3

Distribution:

Unrestricted

Restrictions:

None

Support URL:

http://jevois.org/doc

Other URL:

http://iLab.usc.edu

Address:

University of Southern California, HNB-07A, 3641 Watt Way, Los Angeles, CA 90089-2520, USA