Visual Servoing Platform  version 3.4.0 under development (2021-03-01)
tutorial-matching-keypoint-homography.cpp
1 #include <visp3/core/vpPixelMeterConversion.h>
3 #include <visp3/gui/vpDisplayOpenCV.h>
4 #include <visp3/io/vpVideoReader.h>
5 #include <visp3/vision/vpHomography.h>
6 #include <visp3/vision/vpKeyPoint.h>
7 
8 int main(int argc, const char **argv)
9 {
10 #if (VISP_HAVE_OPENCV_VERSION >= 0x020101)
11  int method = 0;
13 
14  if (argc > 1)
15  method = atoi(argv[1]);
16 
17  if (method == 0)
18  std::cout << "Uses Ransac to estimate the homography" << std::endl;
19  else
20  std::cout << "Uses a robust scheme to estimate the homography" << std::endl;
22 
24 
25  vpVideoReader reader;
26  reader.setFileName("video-postcard.mp4");
27  reader.acquire(I);
28 
29  const std::string detectorName = "ORB";
30  const std::string extractorName = "ORB";
31  // Hamming distance must be used with ORB
32  const std::string matcherName = "BruteForce-Hamming";
34  vpKeyPoint keypoint(detectorName, extractorName, matcherName, filterType);
35  keypoint.buildReference(I);
36 
38  Idisp.resize(I.getHeight(), 2 * I.getWidth());
39  Idisp.insert(I, vpImagePoint(0, 0));
40  Idisp.insert(I, vpImagePoint(0, I.getWidth()));
41 
42  vpDisplayOpenCV d(Idisp, 0, 0, "Homography from matched keypoints");
43  vpDisplay::display(Idisp);
44  vpDisplay::flush(Idisp);
45 
47  vpImagePoint corner_ref[4];
48  corner_ref[0].set_ij(115, 64);
49  corner_ref[1].set_ij(83, 253);
50  corner_ref[2].set_ij(282, 307);
51  corner_ref[3].set_ij(330, 72);
54  for (unsigned int i = 0; i < 4; i++) {
55  vpDisplay::displayCross(Idisp, corner_ref[i], 12, vpColor::red);
56  }
57  vpDisplay::flush(Idisp);
59 
61  vpCameraParameters cam(840, 840, I.getWidth() / 2, I.getHeight() / 2);
63 
64  vpHomography curHref;
65 
66  while (!reader.end()) {
67  reader.acquire(I);
68  Idisp.insert(I, vpImagePoint(0, I.getWidth()));
69  vpDisplay::display(Idisp);
71  vpColor::white, 2);
72 
74  unsigned int nbMatch = keypoint.matchPoint(I);
75  std::cout << "Nb matches: " << nbMatch << std::endl;
77 
78  std::vector<vpImagePoint> iPref(nbMatch),
79  iPcur(nbMatch); // Coordinates in pixels (for display only)
81  std::vector<double> mPref_x(nbMatch), mPref_y(nbMatch);
82  std::vector<double> mPcur_x(nbMatch), mPcur_y(nbMatch);
83  std::vector<bool> inliers(nbMatch);
85 
86  for (unsigned int i = 0; i < nbMatch; i++) {
87  keypoint.getMatchedPoints(i, iPref[i], iPcur[i]);
89  vpPixelMeterConversion::convertPoint(cam, iPref[i], mPref_x[i], mPref_y[i]);
90  vpPixelMeterConversion::convertPoint(cam, iPcur[i], mPcur_x[i], mPcur_y[i]);
92  }
93 
95  try {
96  double residual;
97  if (method == 0)
98  vpHomography::ransac(mPref_x, mPref_y, mPcur_x, mPcur_y, curHref, inliers, residual,
99  (unsigned int)(mPref_x.size() * 0.25), 2.0 / cam.get_px(), true);
100  else
101  vpHomography::robust(mPref_x, mPref_y, mPcur_x, mPcur_y, curHref, inliers, residual, 0.4, 4, true);
102  } catch (...) {
103  std::cout << "Cannot compute homography from matches..." << std::endl;
104  }
105 
107 
109  vpImagePoint corner_cur[4];
110  for (int i = 0; i < 4; i++) {
111  corner_cur[i] = vpHomography::project(cam, curHref, corner_ref[i]);
112  }
114 
116  vpImagePoint offset(0, I.getWidth());
117  for (int i = 0; i < 4; i++) {
118  vpDisplay::displayLine(Idisp, corner_cur[i] + offset, corner_cur[(i + 1) % 4] + offset, vpColor::blue, 3);
119  }
121 
123  for (unsigned int i = 0; i < nbMatch; i++) {
124  if (inliers[i] == true)
125  vpDisplay::displayLine(Idisp, iPref[i], iPcur[i] + offset, vpColor::green);
126  else
127  vpDisplay::displayLine(Idisp, iPref[i], iPcur[i] + offset, vpColor::red);
128  }
130 
131  vpDisplay::flush(Idisp);
132 
133  if (vpDisplay::getClick(Idisp, false))
134  break;
135  }
136 
137  vpDisplay::getClick(Idisp);
138 #else
139  (void)argc;
140  (void)argv;
141 #endif
142  return 0;
143 }
static bool getClick(const vpImage< unsigned char > &I, bool blocking=true)
static vpImagePoint project(const vpCameraParameters &cam, const vpHomography &bHa, const vpImagePoint &iPa)
void resize(unsigned int h, unsigned int w)
resize the image : Image initialization
Definition: vpImage.h:800
Class that enables to manipulate easily a video file or a sequence of images. As it inherits from the...
static void convertPoint(const vpCameraParameters &cam, const double &u, const double &v, double &x, double &y)
static const vpColor green
Definition: vpColor.h:220
static void flush(const vpImage< unsigned char > &I)
static const vpColor red
Definition: vpColor.h:217
Implementation of an homography and operations on homographies.
Definition: vpHomography.h:174
static void display(const vpImage< unsigned char > &I)
The vpDisplayOpenCV allows to display image using the OpenCV library. Thus to enable this class OpenC...
Generic class defining intrinsic camera parameters.
static bool ransac(const std::vector< double > &xb, const std::vector< double > &yb, const std::vector< double > &xa, const std::vector< double > &ya, vpHomography &aHb, std::vector< bool > &inliers, double &residual, unsigned int nbInliersConsensus, double threshold, bool normalization=true)
void acquire(vpImage< vpRGBa > &I)
void insert(const vpImage< Type > &src, const vpImagePoint &topLeft)
Definition: vpImage.h:1115
static void robust(const std::vector< double > &xb, const std::vector< double > &yb, const std::vector< double > &xa, const std::vector< double > &ya, vpHomography &aHb, std::vector< bool > &inlier, double &residual, double weights_threshold=0.4, unsigned int niter=4, bool normalization=true)
static void displayCross(const vpImage< unsigned char > &I, const vpImagePoint &ip, unsigned int size, const vpColor &color, unsigned int thickness=1)
void set_ij(double ii, double jj)
Definition: vpImagePoint.h:188
unsigned int getHeight() const
Definition: vpImage.h:188
Class that allows keypoints detection (and descriptors extraction) and matching thanks to OpenCV libr...
Definition: vpKeyPoint.h:222
vpFilterMatchingType
Definition: vpKeyPoint.h:227
void setFileName(const std::string &filename)
Class that defines a 2D point in an image. This class is useful for image processing and stores only ...
Definition: vpImagePoint.h:87
static const vpColor white
Definition: vpColor.h:212
unsigned int getWidth() const
Definition: vpImage.h:246
static void displayLine(const vpImage< unsigned char > &I, const vpImagePoint &ip1, const vpImagePoint &ip2, const vpColor &color, unsigned int thickness=1, bool segment=true)
static const vpColor blue
Definition: vpColor.h:223