JeVoisBase  1.5
JeVois Smart Embedded Machine Vision Toolkit Base Modules
Share this page:
DemoArUco Class Reference

Simple demo of ArUco augmented reality markers detection and decoding. More...

Inheritance diagram for DemoArUco:
Collaboration diagram for DemoArUco:

Public Member Functions

 DemoArUco (std::string const &instance)
 Constructor. More...
 
virtual ~DemoArUco ()
 Virtual destructor for safe inheritance. More...
 
virtual void process (jevois::InputFrame &&inframe) override
 Processing function, no video output. More...
 
virtual void process (jevois::InputFrame &&inframe, jevois::OutputFrame &&outframe) override
 Processing function with video output to USB. More...
 
- Public Member Functions inherited from jevois::StdModule
 StdModule (std::string const &instance)
 
virtual ~StdModule ()
 
void sendSerialImg1Dx (unsigned int camw, float x, float size=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialStd1Dx (float x, float size=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialImg1Dy (unsigned int camh, float y, float size=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialStd1Dy (float y, float size=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialImg2D (unsigned int camw, unsigned int camh, float x, float y, float w=0.0F, float h=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialStd2D (float x, float y, float w=0.0F, float h=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialContour2D (unsigned int camw, unsigned int camh, std::vector< cv::Point_< T > > points, std::string const &id="", std::string const &extra="")
 
void sendSerialStd3D (float x, float y, float z, float w=0.0F, float h=0.0F, float d=0.0F, float q1=0.0F, float q2=0.0F, float q3=0.0f, float q4=0.0F, std::string const &id="", std::string const &extra="")
 
void sendSerialStd3D (std::vector< cv::Point3f > points, std::string const &id="", std::string const &extra="")
 
- Public Member Functions inherited from jevois::Module
 Module (std::string const &instance)
 
virtual ~Module ()
 
virtual void sendSerial (std::string const &str)
 
virtual void parseSerial (std::string const &str, std::shared_ptr< UserInterface > s)
 
virtual void supportedCommands (std::ostream &os)
 
 JEVOIS_DEFINE_ENUM_CLASS (SerStyle,(Terse)(Normal)(Detail)(Fine)) JEVOIS_DECLARE_PARAMETER(serstyle
 
 JEVOIS_DECLARE_PARAMETER (serprec, unsigned int, "Number of decimal points in standardized serial messages as " "defined in http://jevois.org/doc/UserSerialStyle.html", 0U, ParamCateg)
 
- Public Member Functions inherited from jevois::Component
 Component (std::string const &instance)
 
virtual ~Component ()
 
std::shared_ptr< ComponentgetSubComponent (std::string const &instance) const
 
std::shared_ptr< Comp > addSubComponent (std::string const &instance, Args &&...args)
 
void removeSubComponent (std::shared_ptr< Comp > &component)
 
void removeSubComponent (std::string const &instance, bool warnIfNotFound=true)
 
std::shared_ptr< Comp > getSubComponent (std::string const &instance) const
 
bool isTopLevel () const
 
bool initialized () const
 
std::string const & className () const
 
std::string const & instanceName () const
 
std::vector< std::string > setParamVal (std::string const &paramdescriptor, T const &val)
 
void setParamValUnique (std::string const &paramdescriptor, T const &val)
 
std::vector< std::pair< std::string, T > > getParamVal (std::string const &paramdescriptor) const
 
getParamValUnique (std::string const &paramdescriptor) const
 
std::vector< std::string > setParamString (std::string const &paramdescriptor, std::string const &val)
 
void setParamStringUnique (std::string const &paramdescriptor, std::string const &val)
 
std::vector< std::pair< std::string, std::string > > getParamString (std::string const &paramdescriptor) const
 
std::string getParamStringUnique (std::string const &paramdescriptor) const
 
void freezeParam (std::string const &paramdescriptor)
 
void unFreezeParam (std::string const &paramdescriptor)
 
void freezeAllParams ()
 
void unFreezeAllParams ()
 
std::string descriptor () const
 
void setParamsFromFile (std::string const &filename)
 
std::istream & setParamsFromStream (std::istream &is, std::string const &absfile)
 
void setPath (std::string const &path)
 
std::string absolutePath (std::string const &path="")
 
std::shared_ptr< Comp > addSubComponent (std::string const &instance, Args &&...args)
 
void removeSubComponent (std::shared_ptr< Comp > &component)
 
void removeSubComponent (std::string const &instance, bool warnIfNotFound=true)
 
std::shared_ptr< Comp > getSubComponent (std::string const &instance) const
 
bool isTopLevel () const
 
bool initialized () const
 
std::string const & className () const
 
std::string const & instanceName () const
 
std::vector< std::string > setParamVal (std::string const &paramdescriptor, T const &val)
 
void setParamValUnique (std::string const &paramdescriptor, T const &val)
 
std::vector< std::pair< std::string, T > > getParamVal (std::string const &paramdescriptor) const
 
getParamValUnique (std::string const &paramdescriptor) const
 
std::vector< std::string > setParamString (std::string const &paramdescriptor, std::string const &val)
 
void setParamStringUnique (std::string const &paramdescriptor, std::string const &val)
 
std::vector< std::pair< std::string, std::string > > getParamString (std::string const &paramdescriptor) const
 
std::string getParamStringUnique (std::string const &paramdescriptor) const
 
void freezeParam (std::string const &paramdescriptor)
 
void unFreezeParam (std::string const &paramdescriptor)
 
void freezeAllParams ()
 
void unFreezeAllParams ()
 
std::string descriptor () const
 
void setParamsFromFile (std::string const &filename)
 
std::istream & setParamsFromStream (std::istream &is, std::string const &absfile)
 
void setPath (std::string const &path)
 
std::string absolutePath (std::string const &path="")
 
- Public Member Functions inherited from jevois::ParameterRegistry
virtual ~ParameterRegistry ()
 

Protected Attributes

std::shared_ptr< ArUcoitsArUco
 

Additional Inherited Members

- Protected Member Functions inherited from jevois::Component
virtual void preInit ()
 
virtual void postInit ()
 
virtual void preUninit ()
 
virtual void postUninit ()
 
virtual void preInit ()
 
virtual void postInit ()
 
virtual void preUninit ()
 
virtual void postUninit ()
 
- Protected Member Functions inherited from jevois::ParameterRegistry
void addParameter (ParameterBase *const param)
 
void removeParameter (ParameterBase *const param)
 
void callbackInitCall ()
 

Detailed Description

Simple demo of ArUco augmented reality markers detection and decoding.

Detect and decode patterns known as ArUco markers, which are small 2D barcodes often used in augmented reality and robotics.

ArUco markers are small 2D barcodes. Each ArUco marker corresponds to a number, encoded into a small grid of black and white pixels. The ArUco decoding algorithm is capable of locating, decoding, and of estimating the pose (location and orientation in space) of any ArUco markers in the camera's field of view.

ArUcos are very useful as tags for many robotics and augmented reality applications. For example, one may place an ArUco next to a robot's charging station, an elevator button, or an object that a robot should manipulate.

For more information about ArUco, see https://www.uco.es/investiga/grupos/ava/node/26

The implementation of ArUco used by JeVois is the one of OpenCV-Contrib, documented here: http://docs.opencv.org/3.2.0/d5/dae/tutorial_aruco_detection.html

ArUco markers can be created with several standard dictionaries. Different dictionaries give rise to different numbers of pixels in the markers, and to different numbers of possible symbols that can be created using the dictionary. The default dictionary used by JeVois is 4x4 with 50 symbols. Other dictionaries are also supported by setting the appropriate parameter over serial port or in a config file, up to 7x7 with 1000 symbols.

Creating and printing markers

We have created the 50 markers available in the default dictionary (4x4_50) as PNG images that you can download and print, at http://jevois.org/data/ArUco.zip

To make your own, for example, using another dictionary, see the documentation of the ArUco component of JeVoisBase. Some utilities are provided with the component.

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 ArUco, on every video frame.

2D messages when dopose is off:

  • Serial message type: 2D
  • id: decoded ArUco marker ID, with a prefix 'U'
  • x, y, or vertices: standardized 2D coordinates of marker center or corners
  • w, h: standardized marker size
  • extra: none (empty string)

3D messages when dopose is on:

  • Serial message type: 3D
  • id: decoded ArUco marker ID, with a prefix 'U'
  • 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)

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.

Things to try

  • First, use a video viewer software on a host computer and select one of the video modes with video output over USB. Point your JeVois camera towards one of the screenshots provided with this module, or towards some ArUco markers that you find on the web or that you have printed from the collection above (note: the default dictionary is 4x4_50, see parameter dictionary).
  • Then try it with no video output, as it would be used by a robot. Connect to the command-line interface of your JeVois camera through the serial-over-USB connection (see Command-line interface user guide; on Linux, you would use sudo screen /dev/ttyACM0 115200) and try:
      setpar serout USB
      setmapping2 YUYV 320 240 30.0 JeVois DemoArUco
      streamon
    and point the camera to some markers; the camera should issue messages about all the markers it identifies.

Computing and showing 3D pose

The OpenCV ArUco module can also compute the 3D location and orientation of each marker in the world when dopose is true. The requires that the camera be calibrated, see the documentation of the ArUco component in JeVoisBase. A generic calibration that is for a JeVois camera with standard lens is included in files calibration640x480.yaml, calibration352x288.yaml, etc in the module's directory (on the MicroSD, this is in JEVOIS:/modules/JeVois/DemoArUco/).

When doing pose estimation, you should set the markerlen parameter to the size (width) in millimeters of your actual physical markers. Knowing that size will allow the pose estimation algorithm to know where in the world your detected markers are.

Author
Laurent Itti
Display Name:
Demo ArUco
Videomapping:
NONE 0 0 0 YUYV 320 240 30.0 JeVois DemoArUco
Videomapping:
YUYV 320 260 30.0 YUYV 320 240 30.0 JeVois DemoArUco
Videomapping:
YUYV 640 500 20.0 YUYV 640 480 20.0 JeVois DemoArUco
Email:
itti@usc.edu
Address:
University of Southern California, HNB-07A, 3641 Watt Way, Los Angeles, CA 90089-2520, USA
Main URL:
http://jevois.org
Support URL:
http://jevois.org/doc
Other URL:
http://iLab.usc.edu
License:
GPL v3
Distribution:
Unrestricted
Restrictions:
None

Definition at line 130 of file DemoArUco.C.

Constructor & Destructor Documentation

◆ DemoArUco()

DemoArUco::DemoArUco ( std::string const &  instance)
inline

Constructor.

Definition at line 136 of file DemoArUco.C.

References itsArUco.

◆ ~DemoArUco()

virtual DemoArUco::~DemoArUco ( )
inlinevirtual

Virtual destructor for safe inheritance.

Definition at line 144 of file DemoArUco.C.

Member Function Documentation

◆ process() [1/2]

virtual void DemoArUco::process ( jevois::InputFrame &&  inframe)
inlineoverridevirtual

Processing function, no video output.

Reimplemented from jevois::Module.

Definition at line 150 of file DemoArUco.C.

References jevois::rawimage::convertToCvGray(), jevois::RawImage::height, itsArUco, and jevois::RawImage::width.

◆ process() [2/2]

virtual void DemoArUco::process ( jevois::InputFrame &&  inframe,
jevois::OutputFrame &&  outframe 
)
inlineoverridevirtual

Member Data Documentation

◆ itsArUco

std::shared_ptr<ArUco> DemoArUco::itsArUco
protected

Definition at line 231 of file DemoArUco.C.

Referenced by DemoArUco(), and process().


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