Example: vision_feature_extraction

C++ example source code:

/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          https://www.mrpt.org/                         |
   |                                                                        |
   | Copyright (c) 2005-2024, Individual contributors, see AUTHORS file     |
   | See: https://www.mrpt.org/Authors - All rights reserved.               |
   | Released under BSD License. See: https://www.mrpt.org/License          |
   +------------------------------------------------------------------------+ */

#include <mrpt/gui/CDisplayWindow.h>
#include <mrpt/gui/CDisplayWindow3D.h>
#include <mrpt/vision/CFeatureExtraction.h>
#include <mrpt/vision/tracking.h>

#include <iostream>

using namespace mrpt::gui;
using namespace mrpt::vision;
using namespace mrpt::img;
using namespace mrpt::system;
using namespace std;
using mrpt::format;

#include <mrpt/examples_config.h>
string myDataDir(MRPT_EXAMPLES_BASE_DIRECTORY + string("img_convolution_fft/"));
const string the_img_for_extract_feats = myDataDir + string("test_image.jpg");

// ------------------------------------------------------
//              TestCapture
// ------------------------------------------------------
void TestExtractMatchProjectAndPaint()
{
  CDisplayWindow3D wind;
  CFeatureExtraction fExt;
  CFeatureList featsHarris_L, featsHarris_R;
  CMatchedFeatureList mHarris, mSIFT, mSURF;
  CImage imL, imR;

  string imgL = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_feature_extraction/") +
                string("imgs/imL_p01.jpg");  // Left image
  string imgR = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_feature_extraction/") +
                string("imgs/imR_p01.jpg");  // Right image

  // Load and check images
  if (!imL.loadFromFile(imgL))
  {
    cerr << "Cannot load " << imgL << endl;
    return;
  }
  cout << "Loaded test image: " << imgL << endl;

  if (!imR.loadFromFile(imgR))
  {
    cerr << "Cannot load " << imgR << endl;
    return;
  }
  cout << "Loaded test image: " << imgR << endl;

  cout << "***************************************************" << endl;
  cout << "***************************************************" << endl;

  // Extract features:
  // HARRIS
  cout << "Detecting HARRIS features in LEFT image" << endl;
  fExt.options.featsType = featKLT;
  fExt.detectFeatures(imL, featsHarris_L);
  cout << "Detected " << featsHarris_L.size() << endl;

  cout << "Detecting HARRIS features in RIGHT image" << endl;
  fExt.detectFeatures(imR, featsHarris_R);
  cout << "Detected " << featsHarris_R.size() << endl;

  cout << "***************************************************" << endl;
  cout << "***************************************************" << endl;

  // Match features:
  // size_t nMatches;
  TMatchingOptions opt;

  // HARRIS
  cout << "Matching HARRIS features by CORRELATION" << endl;
  // nMatches =
  matchFeatures(featsHarris_L, featsHarris_R, mHarris);
  cout << "Matches found: " << mHarris.size() << endl;

  cout << "***************************************************" << endl;

}  // end TestExtractMatchProjectAndPaint

// ------------------------------------------------------
//              TestCapture
// ------------------------------------------------------
void TestMatchFeatures()
{
  CDisplayWindow wind, wind2;
  CFeatureExtraction fExt;
  CFeatureList featsHarris_L, featsHarris_R, featsSIFT_L, featsSIFT_R, featsSURF_L, featsSURF_R,
      featsFAST_L, featsFAST_R;
  CMatchedFeatureList mHarris, mSIFT, mSURF, mHarris_SAD, mFAST_CC, mFAST_SAD;
  CImage imL, imR;

  string imgL = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_feature_extraction/") +
                string("imgs/imL_p01.jpg");  // Left image
  string imgR = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_feature_extraction/") +
                string("imgs/imR_p01.jpg");  // Right image

  //    string imgL = "../../bin/imgs/640x480_left_rect.jpg";       // Left
  // image
  //    string imgR = "../../bin/imgs/640x480_right_rect.jpg";      // Right
  // image

  // Load and check images
  if (!imL.loadFromFile(imgL))
  {
    cerr << "Cannot load " << imgL << endl;
    return;
  }
  cout << "Loaded test image: " << imgL << endl;

  if (!imR.loadFromFile(imgR))
  {
    cerr << "Cannot load " << imgR << endl;
    return;
  }
  cout << "Loaded test image: " << imgR << endl;

  cout << "***************************************************" << endl;
  cout << "***************************************************" << endl;

  // Extract features:
  // HARRIS
  cout << "Detecting HARRIS features in LEFT image" << endl;
  fExt.options.featsType = featHarris;
  fExt.detectFeatures(imL, featsHarris_L);
  cout << "Detected " << featsHarris_L.size() << endl;

  cout << "Detecting HARRIS features in RIGHT image" << endl;
  fExt.detectFeatures(imR, featsHarris_R);
  cout << "Detected " << featsHarris_R.size() << endl;
  cout << "***************************************************" << endl;

  // SIFT
  cout << "Detecting SIFT features in LEFT image" << endl;
  fExt.options.featsType = featSIFT;
  fExt.detectFeatures(imL, featsSIFT_L);
  cout << "Detected " << featsSIFT_L.size() << endl;

  cout << "Detecting SIFT features in RIGHT image" << endl;
  fExt.options.featsType = featSIFT;
  fExt.detectFeatures(imR, featsSIFT_R);
  cout << "Detected " << featsSIFT_R.size() << endl;
  cout << "***************************************************" << endl;

  // SURF
  cout << "Detecting SURF features in LEFT image" << endl;
  fExt.options.featsType = featSURF;
  fExt.detectFeatures(imL, featsSURF_L);
  cout << "Detected " << featsSURF_L.size() << endl;

  cout << "Detecting SURF features in RIGHT image" << endl;
  fExt.detectFeatures(imR, featsSURF_R);
  cout << "Detected " << featsSURF_R.size() << endl;
  cout << "***************************************************" << endl;

  // FAST
  cout << "Detecting FAST features in LEFT image" << endl;
  fExt.options.featsType = featFAST;
  fExt.detectFeatures(imL, featsFAST_L, 0, 400);
  cout << "Detected " << featsFAST_L.size() << endl;
  CDisplayWindow fast1("LEFT");
  fast1.showImageAndPoints(imL, featsFAST_L);

  cout << "Detecting FAST features in RIGHT image" << endl;
  fExt.detectFeatures(imR, featsFAST_R, 0, 400);
  cout << "Detected " << featsFAST_R.size() << endl;
  cout << "***************************************************" << endl;
  cout << "***************************************************" << endl;
  CDisplayWindow fast2("RIGHT");
  fast2.showImageAndPoints(imR, featsFAST_R);

  // Match features:
  // size_t nMatches;
  TMatchingOptions opt;

  // HARRIS
  CTicTac tictac;
  cout << "Matching HARRIS features by CORRELATION" << endl;
  tictac.Tic();
  // nMatches =
  matchFeatures(featsHarris_L, featsHarris_R, mHarris);
  double T = tictac.Tac();
  cout << "[CC] Matches found: " << mHarris.size() << " in " << T * 1000.0f << " ms " << endl;

  opt.matching_method = TMatchingOptions::mmSAD;
  tictac.Tic();
  // nMatches =
  matchFeatures(featsHarris_L, featsHarris_R, mHarris_SAD, opt);
  T = tictac.Tac();
  cout << "[SAD] Matches found: " << mHarris_SAD.size() << " in " << T * 1000.0f << " ms " << endl;
  cout << "***************************************************" << endl;
  wind.showImagesAndMatchedPoints(imL, imR, mHarris_SAD, TColor(0, 0, 255));

  // SIFT
  cout << "Matching SIFT features by DESCRIPTOR" << endl;
  opt.matching_method = TMatchingOptions::mmDescriptorSIFT;
  // nMatches =
  matchFeatures(featsSIFT_L, featsSIFT_R, mSIFT, opt);
  cout << "Matches found: " << mSIFT.size() << endl;
  cout << "***************************************************" << endl;

  // SURF
  cout << "Matching SURF features by DESCRIPTOR" << endl;
  opt.matching_method = TMatchingOptions::mmDescriptorSURF;
  // nMatches =
  matchFeatures(featsSURF_L, featsSURF_R, mSURF, opt);
  cout << "Matches found: " << mSURF.size() << endl;
  cout << "***************************************************" << endl;

  // FAST
  cout << "Matching FAST features by CC" << endl;
  tictac.Tic();
  // nMatches =
  matchFeatures(featsFAST_L, featsFAST_R, mFAST_CC);
  T = tictac.Tac();
  cout << "[CC] Matches found: " << mFAST_CC.size() << " in " << T * 1000.0f << " ms " << endl;

  opt.matching_method = TMatchingOptions::mmSAD;
  tictac.Tic();
  // nMatches =
  matchFeatures(featsFAST_L, featsFAST_R, mFAST_SAD, opt);
  T = tictac.Tac();
  cout << "[SAD] Matches found: " << mFAST_SAD.size() << " in " << T * 1000.0f << " ms " << endl;
  cout << "***************************************************" << endl;

  wind2.showImagesAndMatchedPoints(imL, imR, mFAST_SAD, TColor(0, 255, 0));

  mrpt::system::pause();

}  // end TestMatchFeatures

void TestMatchingComparative()
{
  // Take two images
  string imgL = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_feature_extraction/") +
                string("imgs/imL_p01.jpg");  // Left image
  string imgR = MRPT_EXAMPLES_BASE_DIRECTORY + string("vision_feature_extraction/") +
                string("imgs/imR_p01.jpg");  // Right image

  CImage im1, im2;
  bool loadOk = im1.loadFromFile(imgL);
  ASSERT_(loadOk);

  loadOk = im2.loadFromFile(imgR);
  ASSERT_(loadOk);

  size_t imW = im1.getWidth();
  size_t imH = im1.getHeight();

  CFeatureExtraction fExt;
  fExt.options.featsType = featFAST;
  fExt.options.patchSize = 21;

  // Find FAST features
  CFeatureList list1, list2;
  fExt.detectFeatures(im1, list1, 150);
  // Compute SIFT & SURF descriptors
  fExt.computeDescriptors(im1, list1, descSIFT);
  fExt.computeDescriptors(im1, list1, descSURF);

  fExt.detectFeatures(im2, list2, 150);
  // Compute SIFT & SURF descriptors
  fExt.computeDescriptors(im2, list2, descSIFT);
  fExt.computeDescriptors(im2, list2, descSURF);

  im1.drawFeatures(list1);
  im2.drawFeatures(list2);

  CDisplayWindow win, win2;
  win.setPos(0, 0);
  win2.setPos(0, imH * 1.5);
  CImage joinimage, copyjoinimage, copyInfoImage;
  size_t imW2 = 1280;
  size_t imH2 = 150;

  CImage infoimage(imW2, imH2, CH_RGB);

  joinimage.joinImagesHorz(im1, im2);
  infoimage.filledRectangle(0, 0, imW2, imH2, TColor(150, 150, 150));
  infoimage.textOut(20, imH2 - 53, "SAD", TColor::blue());
  infoimage.textOut(20, imH2 - 41, "NCC", TColor::blue());
  infoimage.textOut(20, imH2 - 29, "SIFT", TColor::blue());
  infoimage.textOut(20, imH2 - 17, "SURF", TColor::blue());
  for (auto it1 = list1.begin(); it1 != list1.end(); ++it1)
  {
    const auto& pt1 = it1->keypoint.pt;

    copyInfoImage = infoimage;
    copyjoinimage = joinimage;
    copyjoinimage.line(pt1.x, 0, pt1.x, imH,
                       TColor::green());  // Horiz
    copyjoinimage.line(pt1.x + imW, 0, pt1.x + imW, imH,
                       TColor::green());  // Horiz
    copyjoinimage.line(0, pt1.y, imW + imW, pt1.y,
                       TColor::green());  // Epipolar
    copyjoinimage.drawCircle(pt1.x, pt1.y, 4, TColor::green(),
                             2);  // Keypoint

    copyInfoImage.update_patch(*it1->patch, 0, 0);
    bool firstMatch = true;
    int cnt = 0;
    int px = 80;
    double minsad = 1.0, maxncc = 0.0;
    float minsiftd = 1.0f, minsurfd = 1.0f;
    int idxsad = 0, idxncc = 0, idxsiftd = 0, idxsurfd = 0;

    for (auto it2 = list2.begin(); it2 != list2.end(); ++it2)
    {
      const auto& pt2 = it2->keypoint.pt;

      if (fabs(pt1.y - pt2.y) <= 1.0 && pt1.x > pt2.x)
      {
        // Compute matching with SAD and Correlation and SIFT/SURF?
        // Use epipolar constraints
        // Compute SAD
        double sad = mrpt::vision::computeSAD(*it1->patch, *it2->patch);
        if (sad < minsad)
        {
          minsad = sad;
          idxsad = cnt;
        }
        // Compute Correlation
        double ncc;
        size_t u, v;
        mrpt::vision::openCV_cross_correlation(*it1->patch, *it2->patch, u, v, ncc);
        if (ncc > maxncc)
        {
          maxncc = ncc;
          idxncc = cnt;
        }

        // Compute distance between descriptors SIFT
        float siftd = it1->descriptorSIFTDistanceTo(*it2);
        if (siftd < minsiftd)
        {
          minsiftd = siftd;
          idxsiftd = cnt;
        }

        // Compute distance between descriptors SIFT
        float surfd = it1->descriptorSURFDistanceTo(*it2);
        if (surfd < minsurfd)
        {
          minsurfd = surfd;
          idxsurfd = cnt;
        }

        // Plot images + features + each candidate + difference score
        if (firstMatch)
        {
          copyjoinimage.line(
              pt1.x + imW, 0, pt1.x + imW, imH,
              TColor::green());  // Limit line (only the first time)
          firstMatch = false;
        }  // end-if

        copyjoinimage.drawCircle(pt2.x + imW, pt2.y, 4, TColor::blue(),
                                 2);  // Keypoint
        double rx0, rx1, ry0, ry1, tx, ty;
        rx0 = pt2.x + imW - 15;
        rx1 = pt2.x + imW;
        tx = pt2.x + imW - 13;
        if (cnt % 2)
        {
          ry0 = pt2.y - 20;
          ry1 = pt2.y - 10;
          ty = pt2.y - 22;
        }
        else
        {
          ry0 = pt2.y + 10;
          ry1 = pt2.y + 20;
          ty = pt2.y + 8;
        }
        copyjoinimage.filledRectangle(rx0, ry0, rx1, ry1, TColor(150, 150, 150));
        copyjoinimage.textOut(tx, ty, format("%d", cnt), TColor::blue());

        px = 80 + cnt * 50;
        if (px + fExt.options.patchSize > imW2) continue;

        copyInfoImage.update_patch(*it2->patch, px, 30);

        copyInfoImage.textOut(px, imH2 - 70, format("%d", cnt), TColor::blue());
        copyInfoImage.textOut(px, imH2 - 53, format("%.2f", sad), TColor::blue());
        copyInfoImage.textOut(px, imH2 - 41, format("%.2f", ncc), TColor::blue());
        copyInfoImage.textOut(px, imH2 - 29, format("%.2f", siftd), TColor::blue());
        copyInfoImage.textOut(px, imH2 - 17, format("%.2f", surfd), TColor::blue());

        cnt++;
      }  // end if
    }    // end for it2
    copyInfoImage.textOut(80 + idxsad * 50, imH2 - 53, format("%.2f", minsad), TColor::green());
    copyInfoImage.textOut(80 + idxncc * 50, imH2 - 41, format("%.2f", maxncc), TColor::green());
    copyInfoImage.textOut(80 + idxsiftd * 50, imH2 - 29, format("%.2f", minsiftd), TColor::green());
    copyInfoImage.textOut(80 + idxsurfd * 50, imH2 - 17, format("%.2f", minsurfd), TColor::green());

    win.showImage(copyjoinimage);
    win2.showImage(copyInfoImage);
    mrpt::system::pause();
  }  // end for it1

  // Save to file
  // Check number of good features

}  // end TestMatchingComparative

// ------------------------------------------------------
//              TestExtractFeatures
// ------------------------------------------------------
void TestExtractFeatures()
{
  CDisplayWindow wind1, wind2, wind3, wind4, wind5;
  CFeatureExtraction fExt;
  CFeatureList featsHarris, featsKLT, featsSIFT_Hess, featsSIFT_Lowe, featsSIFT_Vedaldi, featsSURF,
      featsFAST;
  CImage img;

  if (!img.loadFromFile(the_img_for_extract_feats))
  {
    cerr << "Cannot load " << the_img_for_extract_feats << endl;
    return;
  }
  cout << "Loaded test image: " << endl << the_img_for_extract_feats << endl;
  cout << "------------------------------------------------------------------"
          "--------"
       << endl
       << endl;

  CTicTac tictac;

  fExt.options.patchSize = 0;

  cout << "Detect Harris features... [f_harris.txt]" << endl;
  tictac.Tic();
  fExt.options.featsType = featHarris;
  fExt.detectFeatures(img, featsHarris);
  cout << "Detected " << featsHarris.size() << " features in ";
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsHarris.saveToTextFile("f_harris.txt");
  wind1.setWindowTitle("Harris detected features");
  wind1.showImageAndPoints(img, featsHarris);

  cout << "Detect FAST features... [f_fast.txt]" << endl;
  tictac.Tic();
  fExt.options.featsType = featFAST;
  fExt.options.FASTOptions.threshold = 15;  // 150;
  fExt.options.FASTOptions.min_distance = 4;
  fExt.options.FASTOptions.use_KLT_response = true;
  fExt.detectFeatures(img, featsFAST, 0, 500 /* max num feats */);
  cout << "Detected " << featsFAST.size() << " features in ";
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsFAST.saveToTextFile("f_fast.txt");
  wind5.setWindowTitle("FAST detected features");
  wind5.showImageAndPoints(img, featsFAST);

  cout << "Computing SIFT descriptors only ... [f_harris+sift.txt]" << endl;
  tictac.Tic();
  fExt.computeDescriptors(img, featsHarris, descSIFT);
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsHarris.saveToTextFile("f_harris+sift.txt");

  cout << "Extracting KLT features... [f_klt.txt]" << endl;
  tictac.Tic();
  fExt.options.featsType = featKLT;
  fExt.options.KLTOptions.threshold = 0.05f;
  fExt.options.KLTOptions.radius = 5;
  fExt.detectFeatures(img, featsKLT, 0, 10);
  cout << "Detected " << featsKLT.size() << " features in ";
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsKLT.saveToTextFile("f_klt.txt");
  wind2.setWindowTitle("KLT detected features");
  wind2.showImageAndPoints(img, featsKLT);

  cout << "Extracting SIFT features... [f_sift_hess.txt]" << endl;
  tictac.Tic();
  fExt.options.featsType = featSIFT;
  fExt.detectFeatures(img, featsSIFT_Hess);
  cout << "Detected " << featsSIFT_Hess.size() << " features in ";
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsSIFT_Hess.saveToTextFile("f_sift_hess.txt");
  wind3.setWindowTitle("SIFT Hess detected features");
  wind3.showImageAndPoints(img, featsSIFT_Hess);

  cout << "Extracting SURF features... [f_surf.txt]" << endl;
  tictac.Tic();
  fExt.options.featsType = featSURF;
  fExt.detectFeatures(img, featsSURF);
  cout << "Detected " << featsSURF.size() << " features in ";
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsSURF.saveToTextFile("f_surf.txt");
  wind4.setWindowTitle("SURF detected features");
  wind4.showImageAndPoints(img, featsSURF);

  cout << "Computing spin images descriptors only ... [f_harris+spinimgs.txt]" << endl;
  tictac.Tic();
  fExt.options.SpinImagesOptions.radius = 13;
  fExt.options.SpinImagesOptions.hist_size_distance = 10;
  fExt.options.SpinImagesOptions.hist_size_intensity = 10;
  fExt.computeDescriptors(img, featsHarris, descSpinImages);
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl << endl;
  featsHarris.saveToTextFile("f_harris+spinimgs.txt");

  mrpt::system::pause();

  return;
}

void TestExtractFeaturesTile()
{
  CDisplayWindow wind1, wind2;
  CFeatureExtraction fExt;
  CFeatureList featsHarris;
  CImage img;

  string the_img = myDataDir + string("test_image.jpg");

  if (!img.loadFromFile(the_img))
  {
    cerr << "Cannot load " << the_img << endl;
    return;
  }
  cout << "Loaded test image: " << the_img << endl;

  CTicTac tictac;

  cout << "Extracting Harris features (tiled)... [f_harris_tiled.txt]";

  fExt.options.featsType = featHarris;

  tictac.Tic();
  fExt.detectFeatures(img, featsHarris);
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl;

  cout << "Detected " << featsHarris.size() << " features in " << endl;
  featsHarris.saveToTextFile("f_harris_tiled.txt");
  wind1.setWindowTitle("Harris detected features (Tiled image)");
  wind1.showTiledImageAndPoints(img, featsHarris);

  cout << "Extracting Harris features... [f_harris.txt]";

  tictac.Tic();
  fExt.detectFeatures(img, featsHarris);
  cout << format("  %.03fms", tictac.Tac() * 1000) << endl;

  featsHarris.saveToTextFile("f_harris.txt");
  wind2.setWindowTitle("Harris detected features");
  wind2.showTiledImageAndPoints(img, featsHarris);

  mrpt::system::pause();

  return;
}

int main(int argc, char** argv)
{
  try
  {
    TestMatchFeatures();
    // TestExtractFeatures();
    // TestExtractFeaturesTile();
    // TestMatchingComparative();
    // TestORBTiled();

    //      CFeatureList  fs;
    //      fs.loadFromTextFile("f_harris+sift.txt");
    //      fs.saveToTextFile("f_harris+sift2.txt");

    return 0;
  }
  catch (const std::exception& e)
  {
    std::cerr << "MRPT error: " << mrpt::exception_to_str(e) << std::endl;
    return -1;
  }
  catch (...)
  {
    printf("Another exception!!");
    return -1;
  }
}