mbot-apriltag-ibvs.cpp

#include <visp3/core/vpSerial.h>
#include <visp3/core/vpXmlParserCamera.h>
#include <visp3/core/vpMomentObject.h>
#include <visp3/core/vpPoint.h>
#include <visp3/core/vpMomentBasic.h>
#include <visp3/core/vpMomentGravityCenter.h>
#include <visp3/core/vpMomentDatabase.h>
#include <visp3/core/vpMomentCentered.h>
#include <visp3/core/vpMomentAreaNormalized.h>
#include <visp3/core/vpMomentGravityCenterNormalized.h>
#include <visp3/core/vpPixelMeterConversion.h>
#include <visp3/detection/vpDetectorAprilTag.h>
#include <visp3/gui/vpDisplayX.h>
#include <visp3/sensor/vpV4l2Grabber.h>
#include <visp3/io/vpImageIo.h>
#include <visp3/visual_features/vpFeatureMomentAreaNormalized.h>
#include <visp3/visual_features/vpFeatureMomentGravityCenterNormalized.h>
#include <visp3/vs/vpServo.h>
#include <visp3/robot/vpUnicycle.h>

int main(int argc, const char **argv)
{
#if defined(VISP_HAVE_APRILTAG) && defined(VISP_HAVE_V4L2)
  int device = 0;
  vpDetectorAprilTag::vpAprilTagFamily tagFamily = vpDetectorAprilTag::TAG_36h11;
  double tagSize = 0.065;
  float quad_decimate = 4.0;
  int nThreads = 2;
  std::string intrinsic_file = "";
  std::string camera_name = "";
  bool display_tag = false;
  bool display_on = false;
  bool serial_off = false;
  bool save_image = false; // Only possible if display_on = true

  for (int i = 1; i < argc; i++) {
    if (std::string(argv[i]) == "--tag_size" && i + 1 < argc) {
      tagSize = std::atof(argv[i + 1]);
    } else if (std::string(argv[i]) == "--input" && i + 1 < argc) {
      device = std::atoi(argv[i + 1]);
    } else if (std::string(argv[i]) == "--quad_decimate" && i + 1 < argc) {
      quad_decimate = (float)atof(argv[i + 1]);
    } else if (std::string(argv[i]) == "--nthreads" && i + 1 < argc) {
      nThreads = std::atoi(argv[i + 1]);
    } else if (std::string(argv[i]) == "--intrinsic" && i + 1 < argc) {
      intrinsic_file = std::string(argv[i + 1]);
    } else if (std::string(argv[i]) == "--camera_name" && i + 1 < argc) {
      camera_name = std::string(argv[i + 1]);
    } else if (std::string(argv[i]) == "--display_tag") {
      display_tag = true;
#if defined(VISP_HAVE_X11)
    } else if (std::string(argv[i]) == "--display_on") {
      display_on = true;
    } else if (std::string(argv[i]) == "--save_image") {
      save_image = true;
#endif
    } else if (std::string(argv[i]) == "--serial_off") {
      serial_off = true;
    } else if (std::string(argv[i]) == "--tag_family" && i + 1 < argc) {
      tagFamily = (vpDetectorAprilTag::vpAprilTagFamily)std::atoi(argv[i + 1]);
    } else if (std::string(argv[i]) == "--help" || std::string(argv[i]) == "-h") {
      std::cout << "Usage: " << argv[0]
                << " [--input <camera input>] [--tag_size <tag_size in m>]"
                   " [--quad_decimate <quad_decimate>] [--nthreads <nb>]"
                   " [--intrinsic <intrinsic file>] [--camera_name <camera name>]"
                   " [--tag_family <family> (0: TAG_36h11, 1: TAG_36h10, 2: "
                   "TAG_36ARTOOLKIT,"
                   " 3: TAG_25h9, 4: TAG_25h7, 5: TAG_16h5)]"
                   " [--display_tag]";
#if defined(VISP_HAVE_X11)
      std::cout << " [--display_on] [--save_image]";
#endif
      std::cout << " [--serial_off] [--help]" << std::endl;
      return EXIT_SUCCESS;
    }
  }

  // Me Auriga led ring
  // if serial com ok: led 1 green
  // if exception: led 1 red
  // if tag detected: led 2 green, else led 2 red
  // if motor left: led 3 blue
  // if motor right: led 4 blue

  vpSerial *serial = NULL;
  if (! serial_off) {
    serial = new vpSerial("/dev/ttyAMA0", 115200);

    serial->write("LED_RING=0,0,0,0\n");  // Switch off all led
    serial->write("LED_RING=1,0,10,0\n"); // Switch on led 1 to green: serial ok
  }

  try {
    vpImage<unsigned char> I;

    vpV4l2Grabber g;
    std::ostringstream device_name;
    device_name << "/dev/video" << device;
    g.setDevice(device_name.str());
    g.setScale(1);
    g.acquire(I);

    vpDisplay *d = NULL;
    vpImage<vpRGBa> O;
#ifdef VISP_HAVE_X11
    if (display_on) {
      d = new vpDisplayX(I);
    }
#endif

    vpCameraParameters cam;
    cam.initPersProjWithoutDistortion(615.1674805, 615.1675415, I.getWidth() / 2., I.getHeight() / 2.);
#ifdef VISP_HAVE_PUGIXML
    vpXmlParserCamera parser;
    if (!intrinsic_file.empty() && !camera_name.empty())
      parser.parse(cam, intrinsic_file, camera_name, vpCameraParameters::perspectiveProjWithoutDistortion);
#endif
    std::cout << "cam:\n" << cam << std::endl;
    std::cout << "tagFamily: " << tagFamily << std::endl;
    std::cout << "tagSize: " << tagSize << std::endl;

    vpDetectorAprilTag detector(tagFamily);

    detector.setAprilTagQuadDecimate(quad_decimate);
    detector.setAprilTagNbThreads(nThreads);
    detector.setDisplayTag(display_tag);

    vpServo task;
    vpAdaptiveGain lambda;
    if (display_on)
      lambda.initStandard(2.5, 0.4, 30); // lambda(0)=2.5, lambda(oo)=0.4 and lambda'(0)=30
    else
      lambda.initStandard(4, 0.4, 30);   // lambda(0)=4, lambda(oo)=0.4 and lambda'(0)=30

    vpUnicycle robot;
    task.setServo(vpServo::EYEINHAND_L_cVe_eJe);
    task.setInteractionMatrixType(vpServo::CURRENT);
    task.setLambda(lambda);
    vpRotationMatrix cRe;
    cRe[0][0] = 0; cRe[0][1] = -1; cRe[0][2] =  0;
    cRe[1][0] = 0; cRe[1][1] =  0; cRe[1][2] = -1;
    cRe[2][0] = 1; cRe[2][1] =  0; cRe[2][2] =  0;

    vpHomogeneousMatrix cMe(vpTranslationVector(), cRe);
    vpVelocityTwistMatrix cVe(cMe);
    task.set_cVe(cVe);

    vpMatrix eJe(6, 2, 0);
    eJe[0][0] = eJe[5][1] = 1.0;

    std::cout << "eJe: \n" << eJe << std::endl;

    // Desired distance to the target
    double Z_d = 0.4;

    // Define the desired polygon corresponding the the AprilTag CLOCKWISE
    double X[4] = {tagSize/2.,  tagSize/2., -tagSize/2., -tagSize/2.};
    double Y[4] = {tagSize/2., -tagSize/2., -tagSize/2.,  tagSize/2.};
    std::vector<vpPoint> vec_P, vec_P_d;

    for (int i = 0; i < 4; i++) {
      vpPoint P_d(X[i], Y[i], 0);
      vpHomogeneousMatrix cdMo(0, 0, Z_d, 0, 0, 0);
      P_d.track(cdMo); //
      vec_P_d.push_back(P_d);
    }

    vpMomentObject m_obj(3), m_obj_d(3);
    vpMomentDatabase mdb, mdb_d;
    vpMomentBasic mb_d;                                // Here only to get the desired area m00
    vpMomentGravityCenter mg, mg_d;
    vpMomentCentered mc, mc_d;
    vpMomentAreaNormalized man(0, Z_d), man_d(0, Z_d); // Declare normalized area. Desired area parameter will be updated below with m00
    vpMomentGravityCenterNormalized mgn, mgn_d;        // Declare normalized gravity center

    // Desired moments
    m_obj_d.setType(vpMomentObject::DENSE_POLYGON);    // Consider the AprilTag as a polygon
    m_obj_d.fromVector(vec_P_d);                       // Initialize the object with the points coordinates

    mb_d.linkTo(mdb_d);       // Add basic moments to database
    mg_d.linkTo(mdb_d);       // Add gravity center to database
    mc_d.linkTo(mdb_d);       // Add centered moments to database
    man_d.linkTo(mdb_d);      // Add area normalized to database
    mgn_d.linkTo(mdb_d);      // Add gravity center normalized to database
    mdb_d.updateAll(m_obj_d); // All of the moments must be updated, not just an_d
    mg_d.compute();           // Compute gravity center moment
    mc_d.compute();           // Compute centered moments AFTER gravity center

    double area = 0;
    if (m_obj_d.getType() == vpMomentObject::DISCRETE)
      area = mb_d.get(2, 0) + mb_d.get(0, 2);
    else
      area = mb_d.get(0, 0);
    // Update an moment with the desired area
    man_d.setDesiredArea(area);

    man_d.compute();          // Compute area normalized moment AFTER centered moments
    mgn_d.compute();          // Compute gravity center normalized moment AFTER area normalized moment

    // Desired plane
    double A = 0.0;
    double B = 0.0;
    double C = 1.0 / Z_d;

    // Construct area normalized features
    vpFeatureMomentGravityCenterNormalized s_mgn(mdb, A, B, C), s_mgn_d(mdb_d, A, B, C);
    vpFeatureMomentAreaNormalized s_man(mdb, A, B, C), s_man_d(mdb_d, A, B, C);

    // Add the features
    task.addFeature(s_mgn, s_mgn_d, vpFeatureMomentGravityCenterNormalized::selectXn());
    task.addFeature(s_man, s_man_d);

    // Update desired gravity center normalized feature
    s_mgn_d.update(A, B, C);
    s_mgn_d.compute_interaction();
    // Update desired area normalized feature
    s_man_d.update(A, B, C);
    s_man_d.compute_interaction();

    std::vector<double> time_vec;
    for (;;) {
      g.acquire(I);

      vpDisplay::display(I);

      double t = vpTime::measureTimeMs();
      std::vector<vpHomogeneousMatrix> cMo_vec;
      detector.detect(I, tagSize, cam, cMo_vec);
      t = vpTime::measureTimeMs() - t;
      time_vec.push_back(t);

      {
        std::stringstream ss;
        ss << "Detection time: " << t << " ms";
        vpDisplay::displayText(I, 40, 20, ss.str(), vpColor::red);
      }

      if (detector.getNbObjects() == 1) {
        if (! serial_off) {
          serial->write("LED_RING=2,0,10,0\n"); // Switch on led 2 to green: tag detected
        }

        // Update current points used to compute the moments
        std::vector< vpImagePoint > vec_ip = detector.getPolygon(0);
        vec_P.clear();
        for (size_t i = 0; i < vec_ip.size(); i++) { // size = 4
          double x = 0, y = 0;
          vpPixelMeterConversion::convertPoint(cam, vec_ip[i], x, y);
          vpPoint P;
          P.set_x(x);
          P.set_y(y);
          vec_P.push_back(P);
        }

        // Display visual features
        vpDisplay::displayPolygon(I, vec_ip, vpColor::green, 3); // Current polygon used to compure an moment
        vpDisplay::displayCross(I, detector.getCog(0), 15, vpColor::green, 3); // Current polygon used to compure an moment
        vpDisplay::displayLine(I, 0, cam.get_u0(), I.getHeight()-1, cam.get_u0(), vpColor::red, 3); // Vertical line as desired x position

        // Current moments
        m_obj.setType(vpMomentObject::DENSE_POLYGON); // Consider the AprilTag as a polygon
        m_obj.fromVector(vec_P);                      // Initialize the object with the points coordinates

        mg.linkTo(mdb);           // Add gravity center to database
        mc.linkTo(mdb);           // Add centered moments to database
        man.linkTo(mdb);          // Add area normalized to database
        mgn.linkTo(mdb);          // Add gravity center normalized to database
        mdb.updateAll(m_obj);     // All of the moments must be updated, not just an_d
        mg.compute();             // Compute gravity center moment
        mc.compute();             // Compute centered moments AFTER gravity center
        man.setDesiredArea(area); // Since desired area was init at 0, because unknow at contruction, need to be updated here
        man.compute();            // Compute area normalized moment AFTER centered moment
        mgn.compute();            // Compute gravity center normalized moment AFTER area normalized moment

        s_mgn.update(A, B, C);
        s_mgn.compute_interaction();
        s_man.update(A, B, C);
        s_man.compute_interaction();

        task.set_cVe(cVe);
        task.set_eJe(eJe);

        // Compute the control law. Velocities are computed in the mobile robot reference frame
        vpColVector v = task.computeControlLaw();

        std::cout << "Send velocity to the mbot: " << v[0] << " m/s " << vpMath::deg(v[1]) << " deg/s" << std::endl;

        task.print();
        double radius = 0.0325;
        double L = 0.0725;
        double motor_left  = (-v[0] - L * v[1]) / radius;
        double motor_right = ( v[0] - L * v[1]) / radius;
        std::cout << "motor left vel: " << motor_left << " motor right vel: " << motor_right << std::endl;
        if (! serial_off) {
//          serial->write("LED_RING=3,0,0,10\n"); // Switch on led 3 to blue: motor left servoed
//          serial->write("LED_RING=4,0,0,10\n"); // Switch on led 4 to blue: motor right servoed
        }
        std::stringstream ss;
        double rpm_left  = motor_left  * 30. / M_PI;
        double rpm_right = motor_right * 30. / M_PI;
        ss << "MOTOR_RPM=" << vpMath::round(rpm_left) << "," << vpMath::round(rpm_right) << "\n";
        std::cout << "Send: " << ss.str() << std::endl;
        if (! serial_off) {
          serial->write(ss.str());
        }
      }
      else {
        // stop the robot
        if (! serial_off) {
          serial->write("LED_RING=2,10,0,0\n"); // Switch on led 2 to red: tag not detected
//          serial->write("LED_RING=3,0,0,0\n");  // Switch on led 3 to blue: motor left not servoed
//          serial->write("LED_RING=4,0,0,0\n");  // Switch on led 4 to blue: motor right not servoed
          serial->write("MOTOR_RPM=0,-0\n");    // Stop the robot
        }
      }

      vpDisplay::displayText(I, 20, 20, "Click to quit.", vpColor::red);
      vpDisplay::flush(I);

      if (display_on && save_image) {
        vpDisplay::getImage(I, O);
        vpImageIo::write(O, "image.png");
      }
      if (vpDisplay::getClick(I, false))
        break;
    }

    if (! serial_off) {
      serial->write("LED_RING=0,0,0,0\n"); // Switch off all led
    }

    std::cout << "Benchmark computation time" << std::endl;
    std::cout << "Mean / Median / Std: " << vpMath::getMean(time_vec) << " ms"
              << " ; " << vpMath::getMedian(time_vec) << " ms"
              << " ; " << vpMath::getStdev(time_vec) << " ms" << std::endl;

    if (display_on)
      delete d;
    if (! serial_off) {
      delete serial;
    }
  } catch (const vpException &e) {
    std::cerr << "Catch an exception: " << e.getMessage() << std::endl;
    if (! serial_off) {
      serial->write("LED_RING=1,10,0,0\n"); // Switch on led 1 to red
    }
  }

  return EXIT_SUCCESS;
#else
  (void)argc;
  (void)argv;
#ifndef VISP_HAVE_APRILTAG
  std::cout << "ViSP is not build with Apriltag support" << std::endl;
#endif
#ifndef VISP_HAVE_V4L2
  std::cout << "ViSP is not build with v4l2 support" << std::endl;
#endif
  std::cout << "Install missing 3rd parties, configure and build ViSP to run this tutorial" << std::endl;
  return EXIT_SUCCESS;
#endif
}