Visual Servoing Platform  version 3.6.1 under development (2024-05-26)
#include <visp3/core/vpConfig.h>
#include <visp3/core/vpImageConvert.h>
#include <visp3/detection/vpDetectorDataMatrixCode.h>
#include <visp3/detection/vpDetectorQRCode.h>
#include <visp3/gui/vpDisplayGDI.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/sensor/vpV4l2Grabber.h>
#include <opencv2/videoio.hpp>
int main(int argc, const char **argv)
#if (defined(VISP_HAVE_V4L2) || defined(HAVE_OPENCV_VIDEOIO)) && (defined(VISP_HAVE_ZBAR) || defined(VISP_HAVE_DMTX))
int opt_device = 0;
int opt_barcode = 0; // 0=QRCode, 1=DataMatrix
for (int i = 0; i < argc; i++) {
if (std::string(argv[i]) == "--device")
opt_device = atoi(argv[i + 1]);
else if (std::string(argv[i]) == "--code-type")
opt_barcode = atoi(argv[i + 1]);
else if (std::string(argv[i]) == "--help" || std::string(argv[i]) == "-h") {
std::cout << "Usage: " << argv[0]
<< " [--device <camera number>] [--code-type <0 for QR code | "
"1 for DataMatrix code>] [--help] [-h]"
<< std::endl;
std::cout << "Use device: " << opt_device << std::endl;
try {
vpImage<unsigned char> I; // for gray images
#if defined(VISP_HAVE_V4L2)
std::ostringstream device;
device << "/dev/video" << opt_device;
#elif defined(HAVE_OPENCV_VIDEOIO)
cv::VideoCapture cap(opt_device); // open the default camera
if (!cap.isOpened()) { // check if we succeeded
std::cout << "Failed to open the camera" << std::endl;
cv::Mat frame;
cap >> frame; // get a new frame from camera
#if defined(VISP_HAVE_X11)
vpDisplayX d(I);
#elif defined(VISP_HAVE_GDI)
#elif defined(HAVE_OPENCV_HIGHGUI)
vpDisplay::setTitle(I, "ViSP viewer");
vpDetectorBase *detector = nullptr;
#if (defined(VISP_HAVE_ZBAR) && defined(VISP_HAVE_DMTX))
if (opt_barcode == 0)
detector = new vpDetectorQRCode;
detector = new vpDetectorDataMatrixCode;
#elif defined(VISP_HAVE_ZBAR)
detector = new vpDetectorQRCode;
#elif defined(VISP_HAVE_DMTX)
detector = new vpDetectorDataMatrixCode;
for (;;) {
#if defined(VISP_HAVE_V4L2)
#elif defined(HAVE_OPENCV_VIDEOIO)
cap >> frame; // get a new frame from camera
bool status = detector->detect(I);
std::ostringstream legend;
legend << detector->getNbObjects() << " bar code detected";
vpDisplay::displayText(I, 10, 10, legend.str(), vpColor::red);
if (status) {
for (size_t i = 0; i < detector->getNbObjects(); i++) {
std::vector<vpImagePoint> p = detector->getPolygon(i);
vpRect bbox = detector->getBBox(i);
vpDisplay::displayText(I, (int)bbox.getTop() - 20, (int)bbox.getLeft(),
"Message: \"" + detector->getMessage(i) + "\"", vpColor::red);
for (size_t j = 0; j < p.size(); j++) {
std::ostringstream number;
number << j;
vpDisplay::displayText(I, p[j] + vpImagePoint(10, 0), number.str(), vpColor::blue);
vpDisplay::displayText(I, (int)I.getHeight() - 25, 10, "Click to quit...", vpColor::red);
if (vpDisplay::getClick(I, false)) // a click to exit
delete detector;
catch (const vpException &e) {
std::cout << "Catch an exception: " << e << std::endl;
static const vpColor red
Definition: vpColor.h:211
static const vpColor blue
Definition: vpColor.h:217
static const vpColor green
Definition: vpColor.h:214
std::vector< std::vector< vpImagePoint > > & getPolygon()
vpRect getBBox(size_t i) const
size_t getNbObjects() const
std::vector< std::string > & getMessage()
virtual bool detect(const vpImage< unsigned char > &I)=0
Display for windows using GDI (available on any windows 32 platform).
Definition: vpDisplayGDI.h:128
The vpDisplayOpenCV allows to display image using the OpenCV library. Thus to enable this class OpenC...
Use the X11 console to display images on unix-like OS. Thus to enable this class X11 should be instal...
Definition: vpDisplayX.h:128
static bool getClick(const vpImage< unsigned char > &I, bool blocking=true)
static void display(const vpImage< unsigned char > &I)
static void displayCross(const vpImage< unsigned char > &I, const vpImagePoint &ip, unsigned int size, const vpColor &color, unsigned int thickness=1)
static void setTitle(const vpImage< unsigned char > &I, const std::string &windowtitle)
static void flush(const vpImage< unsigned char > &I)
static void displayRectangle(const vpImage< unsigned char > &I, const vpImagePoint &topLeft, unsigned int width, unsigned int height, const vpColor &color, bool fill=false, unsigned int thickness=1)
static void displayText(const vpImage< unsigned char > &I, const vpImagePoint &ip, const std::string &s, const vpColor &color)
error that can be emitted by ViSP classes.
Definition: vpException.h:59
static void convert(const vpImage< unsigned char > &src, vpImage< vpRGBa > &dest)
Class that defines a 2D point in an image. This class is useful for image processing and stores only ...
Definition: vpImagePoint.h:82
unsigned int getHeight() const
Definition: vpImage.h:184
Defines a rectangle in the plane.
Definition: vpRect.h:76
double getLeft() const
Definition: vpRect.h:170
double getTop() const
Definition: vpRect.h:189
Class that is a wrapper over the Video4Linux2 (V4L2) driver.
void setScale(unsigned scale=vpV4l2Grabber::DEFAULT_SCALE)
void setDevice(const std::string &devname)
void acquire(vpImage< unsigned char > &I)