#include <vpDetectorDataMatrixCode.h>

Inheritance diagram for vpDetectorDataMatrixCode:

Public Member Functions
	vpDetectorDataMatrixCode ()
bool	detect (const vpImage< unsigned char > &I) VP_OVERRIDE

Inherited functionalities from vpDetectorBase
vpRect	getBBox (size_t i) const
vpImagePoint	getCog (size_t i) const
std::vector< std::string > &	getMessage ()
std::string &	getMessage (size_t i)
size_t	getNbObjects () const
std::vector< std::vector< vpImagePoint > > &	getPolygon ()
std::vector< vpImagePoint > &	getPolygon (size_t i)
void	setTimeout (unsigned long timeout_ms)
std::vector< std::vector< vpImagePoint > >	m_polygon
std::vector< std::string >	m_message
size_t	m_nb_objects
unsigned long	m_timeout_ms

Detailed Description

Base class for bar code detector. This class is a wrapper over libdmtx available from http://www.libdmtx.org. Installation instructions are provided here https://visp.inria.fr/3rd_dmtx.

The detect() function allows to detect multiple QR codes in an image. Once detected, for each QR code it is possible to retrieve the location of the corners using getPolygon(), the encoded message using getMessage(), the bounding box using getBBox() and the center of gravity using getCog().

The following sample code shows how to use this class to detect QR codes in an image.

#include <visp3/detection/vpDetectorDataMatrixCode.h>
#include <visp3/io/vpImageIo.h>
 
#ifdef ENABLE_VISP_NAMESPACE
using namespace VISP_NAMESPACE_NAME;
#endif
 
int main()
{
#ifdef VISP_HAVE_DMTX
  vpImage<unsigned char> I;
  vpImageIo::read(I, "bar-code.jpg");
 
  vpDetectorDataMatrixCode detector;
 
  bool status = detector.detect(I);
  if (status) {
    for(size_t i=0; i < detector.getNbObjects(); i++) {
      std::cout << "Bar code " << i << ":" << std::endl;
      std::vector<vpImagePoint> p = detector.getPolygon(i);
      for(size_t j=0; j < p.size(); j++)
        std::cout << "  Point " << j << ": " << p[j] << std::endl;
      std::cout << "  Message: \"" << detector.getMessage(i) << "\"" << std::endl;
    }
  }
#endif
}

The previous example may produce results like:

Bar code 0:
  Point 0: 273.21, 78.9799
  Point 1: 390.016, 85.1014
  Point 2: 388.024, 199.185
  Point 3: 269.23, 192.96
  Message: "datamatrix 1"
Bar code 1:
  Point 0: 262.23, 396.404
  Point 1: 381.041, 402.631
  Point 2: 378.92, 524.188
  Point 3: 257.916, 519.962
  Message: "datamatrix 2"

Tutorials & Examples

Tutorials
If you are interested in multiple QR codes detection, you may have a look at:

Tutorial: Bar code detection

Examples: tutorial-barcode-detector-live.cpp, and tutorial-barcode-detector.cpp.

Definition at line 116 of file vpDetectorDataMatrixCode.h.

Constructor & Destructor Documentation

◆ vpDetectorDataMatrixCode()

BEGIN_VISP_NAMESPACE vpDetectorDataMatrixCode::vpDetectorDataMatrixCode ( )

Default constructor that does nothing except setting detection timeout to 50ms. This value could be changed using setTimeout().

Definition at line 49 of file vpDetectorDataMatrixCode.cpp.

References vpDetectorBase::setTimeout().

Member Function Documentation

◆ detect()

bool vpDetectorDataMatrixCode::detect ( const vpImage< unsigned char > & I )

virtual

Detect datamatrix codes in the image. Return true if a code is detected, false otherwise. There is the setTimeout() function that allows to tune the value of the timeout used to detect a datamatrix code. By default, there is a timeout of 50 ms set in the constructor.

Parameters