Visual Servoing Platform  version 3.5.1 under development (2023-02-03)
#include <visp3/core/vpConfig.h>
#include <visp3/sensor/vpV4l2Grabber.h>
#include <visp3/core/vpImageConvert.h>
#include <visp3/gui/vpDisplayOpenCV.h>
#include <visp3/io/vpVideoReader.h>
#include <visp3/klt/vpKltOpencv.h>
int main(int argc, const char *argv[])
#if defined(VISP_HAVE_OPENCV) && (defined(VISP_HAVE_V4L2) || (VISP_HAVE_OPENCV_VERSION >= 0x020100))
try {
bool opt_init_by_click = false;
int opt_device = 0;
for (int i = 0; i < argc; i++) {
if (std::string(argv[i]) == "--init-by-click")
opt_init_by_click = true;
else if (std::string(argv[i]) == "--device")
opt_device = atoi(argv[i + 1]);
else if (std::string(argv[i]) == "--help") {
std::cout << "Usage: " << argv[0] << " [--init-by-click] [--device <camera device>] [--help]" << std::endl;
return 0;
#if defined(VISP_HAVE_V4L2)
std::ostringstream device;
device << "/dev/video" << opt_device;
#elif defined(VISP_HAVE_OPENCV)
cv::VideoCapture g(opt_device);
if (!g.isOpened()) { // check if we succeeded
std::cout << "Failed to open the camera" << std::endl;
return -1;
cv::Mat frame;
g >> frame; // get a new frame from camera
IplImage *cvI = NULL;
cv::Mat cvI;
// Display initialisation
vpDisplayOpenCV d(I, 0, 0, "Klt tracking");
vpKltOpencv tracker;
// Set tracker parameters
// Initialise the tracking
if (opt_init_by_click) {
#if (VISP_HAVE_OPENCV_VERSION >= 0x020408)
std::vector<cv::Point2f> guess;
do {
vpDisplay::displayText(I, 10, 10, "Left click to select a point, right to start tracking", vpColor::red);
if (vpDisplay::getClick(I, ip, button, false)) {
if (button == vpMouseButton::button1) {
guess.push_back(cv::Point2f((float)ip.get_u(), (float)ip.get_v()));
vpDisplay::displayText(I, 10, 10, "Left click to select a point, right to start tracking", vpColor::red);
} while (button != vpMouseButton::button3);
tracker.initTracking(cvI, guess);
} else {
while (1) {
#if defined(VISP_HAVE_V4L2)
#elif defined(VISP_HAVE_OPENCV)
g >> frame;
tracker.display(I, vpColor::red);
vpDisplay::displayText(I, 10, 10, "Click to quit", vpColor::red);
if (vpDisplay::getClick(I, false))
return 0;
} catch (const vpException &e) {
std::cout << "Catch an exception: " << e << std::endl;
static const vpColor red
Definition: vpColor.h:217
static const vpColor green
Definition: vpColor.h:220
The vpDisplayOpenCV allows to display image using the OpenCV library. Thus to enable this class OpenC...
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 flush(const vpImage< unsigned char > &I)
static void displayText(const vpImage< unsigned char > &I, const vpImagePoint &ip, const std::string &s, const vpColor &color)
error that can be emited by ViSP classes.
Definition: vpException.h:72
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:89
double get_u() const
Definition: vpImagePoint.h:143
double get_v() const
Definition: vpImagePoint.h:154
Wrapper for the KLT (Kanade-Lucas-Tomasi) feature tracker implemented in OpenCV. Thus to enable this ...
Definition: vpKltOpencv.h:79
void setBlockSize(int blockSize)
void setQuality(double qualityLevel)
void track(const cv::Mat &I)
void setHarrisFreeParameter(double harris_k)
void setMaxFeatures(int maxCount)
void initTracking(const cv::Mat &I, const cv::Mat &mask=cv::Mat())
void setMinDistance(double minDistance)
void display(const vpImage< unsigned char > &I, const vpColor &color=vpColor::red, unsigned int thickness=1)
void setUseHarris(int useHarrisDetector)
void setWindowSize(int winSize)
void setPyramidLevels(int pyrMaxLevel)
Class that is a wrapper over the Video4Linux2 (V4L2) driver.
void open(vpImage< unsigned char > &I)
void setDevice(const std::string &devname)
void acquire(vpImage< unsigned char > &I)
VISP_EXPORT int wait(double t0, double t)