void RobustMatcher::robustMatch( const cv::Mat& frame, std::vector<cv::DMatch>& good_matches,
std::vector<cv::KeyPoint>& keypoints_frame, const cv::Mat& descriptors_model )
{
// 1a. Detection of the ORB features
this->computeKeyPoints(frame, keypoints_frame);
// 1b. Extraction of the ORB descriptors
cv::Mat descriptors_frame;
this->computeDescriptors(frame, keypoints_frame, descriptors_frame);
// 2. Match the two image descriptors
std::vector<std::vector<cv::DMatch> > matches12, matches21;
// 2a. From image 1 to image 2
matcher_->knnMatch(descriptors_frame, descriptors_model, matches12, 2); // return 2 nearest neighbours
// 2b. From image 2 to image 1
matcher_->knnMatch(descriptors_model, descriptors_frame, matches21, 2); // return 2 nearest neighbours
// 3. Remove matches for which NN ratio is > than threshold
// clean image 1 -> image 2 matches
ratioTest(matches12);
// clean image 2 -> image 1 matches
ratioTest(matches21);
// 4. Remove non-symmetrical matches
symmetryTest(matches12, matches21, good_matches);
}
void SymmetryNNDRMatcher::match(Mat &descriptors_object, Mat &descriptors_scene, std::vector<DMatch> &good_matches)
{
cv::BruteForceMatcher<cv::L2<float> > matcher;
// Match all keypoints from the object to the scene
std::vector<std::vector<cv::DMatch> > matches1;
matcher.knnMatch(descriptors_object, descriptors_scene,
matches1, // Vector of matches
2); // return 2 nearest neighbours
// Match all keypoints from the scene with the object
std::vector<std::vector<cv::DMatch> > matches2;
matcher.knnMatch(descriptors_scene, descriptors_object,
matches2, // Vector of matches
2); // return 2 nearest neighbours
// Check NNDR for both match vectors
ratioTest(matches1);
ratioTest(matches2);
// Remove non-symmetrical matches
// std::vector<cv::DMatch> symMatches;
symmetryTest(matches1,matches2,good_matches);
}
// Main method:
cv::Mat RobustMatcher::match(cv::Mat &image1,
cv::Mat &image2,
std::vector<cv::DMatch> &matches,
std::vector<cv::KeyPoint> &keypoints1,
std::vector<cv::KeyPoint> &keypoints2){
// 1a. Detection of the SURF features
detector->detect(image1,keypoints1);
detector->detect(image2,keypoints2);
// 1b. Extraction of the SURF descriptors
cv::Mat descriptors1, descriptors2;
extractor->compute(image1,keypoints1,descriptors1);
extractor->compute(image2,keypoints2,descriptors2);
// 2. Match the two image descriptors
// Construction of the matcher
//cv::BruteForceMatcher< cv::L2<float> > matcher;
cv::FlannBasedMatcher matcher;
// from image 1 to image 2
// based on k nearest neighbours (with k=2)
std::vector< std::vector<cv::DMatch> > matches1;
matcher.knnMatch(descriptors1,descriptors2,
matches1, // vector of matches (up to 2 per entry)
2);
// return 2 nearest neighbours
// from image 2 to image 1
// based on k nearest neighbours (with k=2)
std::vector< std::vector<cv::DMatch> > matches2;
matcher.knnMatch(descriptors2,descriptors1,
matches2, // vector of matches (up to 2 per entry)
2);
// return 2 nearest neighbours
// 3. Remove matches for which NN ratio is
// > than threshold
// clean image 1 -> image 2 matches
int removed= ratioTest(matches1);
// clean image 2 -> image 1 matches
removed= ratioTest(matches2);
// 4. Remove non-symmetrical matches
std::vector<cv::DMatch> symMatches;
symmetryTest(matches1,matches2,symMatches);
// 5. Validate matches using RANSAC
cv::Mat fundemental= ransacTest(symMatches,
keypoints1, keypoints2, matches);
// return the found fundemental matrix
return fundemental;
}
/* Calculation of Homography for feature based
*
**/
void AlignmentMatrixCalc::featureBasedHomography()
{
std::vector<cv::DMatch> matchesPrevToCurrent;
std::vector<cv::DMatch> matchesCurrentToPrev;
std::vector<std::vector<cv::DMatch> > kmatchesPrevToCurrent;
std::vector<std::vector<cv::DMatch> > kmatchesCurrentToPrev;
std::vector<cv::DMatch> matchesPassed;
// Matching Section begin
if( matchType == normalMatch )
{
matcher->match( descriptorsPrev, descriptorsCurrent, matchesPrevToCurrent );
matcher->match( descriptorsCurrent, descriptorsPrev, matchesCurrentToPrev );
// Symmetry Test start
symmetryTest(matchesPrevToCurrent, matchesCurrentToPrev, matchesPassed);
}
else if( matchType == knnMatch)
{
// qDebug()<<"Match : "<<keypointsCurrent.size()<<" "<<keypointsPrev.size()<<"\n";
matcher->knnMatch(descriptorsPrev, descriptorsCurrent, kmatchesPrevToCurrent,2);
// qDebug()<<"Ratio Test 1 :"<<kmatchesPrevToCurrent.size()<<"\n";
ratioTest(kmatchesPrevToCurrent);
// qDebug()<<"Ratio Test 1 End :"<<kmatchesPrevToCurrent.size()<<"\n";
matcher->knnMatch(descriptorsCurrent,descriptorsPrev, kmatchesCurrentToPrev, 2);
// qDebug()<<"Ratio Test 2 :"<<kmatchesCurrentToPrev.size()<<"\n";
ratioTest(kmatchesCurrentToPrev);
// qDebug()<<"Ratio Test 2 End :"<<kmatchesCurrentToPrev.size()<<"\n";
// Symmetry Test not working for knn
//matchesPassed=matchesPrevToCurrent;
symmetryTest(kmatchesPrevToCurrent,kmatchesCurrentToPrev,matchesPassed);
// qDebug()<<"Sym Test :"<<matchesPassed.size()<<"\n";
}
else if( matchType == radiusMatch)
{
// there is no documentation
// matcher->radiusMatch(descriptorsPrev, descriptorsCurrent, kmatchesPrevToCurrent,maxRadius );
// work but there is no matching back for any maxRadius
//convertRMatches(kmatchesCurrentToPrev,matchesPassed);
exc.showException("radiusMatch not working Dont use it!" );
}
// Matching Section end
isHomographyCalc = false;
pointsPrev.clear();
pointsCurrent.clear();
// Conversition of matched Keypoints to points
for (int p = 0; p < (int)matchesPassed.size(); ++p)
{
pointsPrev.push_back(keypointsPrev[matchesPassed[p].queryIdx].pt);
pointsCurrent.push_back(keypointsCurrent[matchesPassed[p].trainIdx].pt);
}
// if enough matched points exist
if(pointsPrev.size() >= 4 && pointsCurrent.size() >= 4)
{
// Sub-pixsel Accuracy
cv::cornerSubPix(prevFrame, pointsPrev, cv::Size(5,5), cv::Size(-1,-1),
cv::TermCriteria(cv::TermCriteria::MAX_ITER+cv::TermCriteria::EPS,30,0.1));
cv::cornerSubPix(currentFrame, pointsCurrent, cv::Size(5,5), cv::Size(-1,-1),
cv::TermCriteria(cv::TermCriteria::MAX_ITER+cv::TermCriteria::EPS,30,0.1));
homography = cv::findHomography(pointsPrev, pointsCurrent, homographyCalcMethod,
ransacReprojThreshold);
/*
cv::findHomography can return empty matrix in some cases.
This seems happen only when cv::RANSAC flag is passed.
check the computed homography before using it
*/
if(!homography.empty())
{
if(isHomographyValid()) //
{
isHomographyCalc = true;
}
}
}
if(isHomographyCalc == false)
{
// if valid homography not calculated returns to a second stage....
stage=secondPass;
}
}
// Match feature points using symmetry test and RANSAC
// returns fundemental matrix
bool feature_matcher::match(cv::Mat& image1, cv::Mat& image2, // input images
std::vector<cv::DMatch>& matches, // output matches and keypoints
std::vector<cv::KeyPoint>& keypoints1, std::vector<cv::KeyPoint>& keypoints2) {
ros::Time startTime = ros::Time::now();
cv::Mat matchesMat;
std::stringstream onScreenText;
// cleaning..
int imageMatches;
imageMatches= imageMatches+0;
matches.clear();
keypoints1.clear();
highestComp = 0.;
/*
cv::createTrackbar("ConfidenceLevel [%] : ", "FEATURE REF", &Trackbar1, 100, NULL);
cv::createTrackbar("MinDistanceToEpipolar: ", "FEATURE REF", &Trackbar2, 10, NULL);
cv::createTrackbar("Ratio [%]: ", "FEATURE REF", &Trackbar3, 100, NULL);
cv::createTrackbar("Min. Matches: ", "FEATURE REF", &Trackbar4, 200, NULL);
*/
// 1a. Detection of the SURF/SIFT features
detector->detect(image1,keypoints1);
std::cout << keypoints1.size() << " Keypoints extracted from Label" << std::endl;
info_lastMatch.imageKeys = keypoints1.size();
// 1b. Extraction of the SURF/SIFT descriptors
cv::Mat descriptors1, descriptors2;
extractor->compute(image1,keypoints1,descriptors1);
//extractor->compute(image2,keypoints2,descriptors2);
//std::cout << "descriptor matrix size: " << descriptors1.rows << " by " << descriptors1.cols << std::endl;
cv::Mat tmp;
this->allReferences.copyTo(tmp);
onScreenText.str(std::string());
onScreenText << "Keypoints on Scene-Label: " << keypoints1.size();
cv::putText(tmp, onScreenText.str(), cv::Point(10, this->allReferences.rows - 50), CV_FONT_HERSHEY_SIMPLEX, 0.50, cv::Scalar(200, 200, 0), 1, CV_AA);
std::cout << "Matching with references (ratio test) : " << std::endl;
printf("Ref1\tRef2\tRef3\tRef4\tRef5\tRef6\tRef7\tRef8");
std::cout << std::endl;
if (descriptors1.rows == 0 || descriptors1.cols == 0) {
printf("0\t0\t0\t0\t0\t0\t0\t0\n");
printf("No Keypoints identified from camera. ??Looking at a plain scene??\n");
return false;
}
int featureMatches[2][numOfRefPics];
int positiveRef;
float highestMatch;
std::vector<std::vector<cv::DMatch> > bestMatches;
cv::Mat bestDescriptors;
std::vector<cv::KeyPoint> bestKeypoints;
std::stringstream resultText;
positiveRef=-1;
highestMatch=-1;
resultText.str(std::string());
for (uint i = 0; (i < (this->referencePics).size()); i++) {
// take the right Pic/KP/Desc of the Array and store it in XXX2 <- only for easier handling
keypoints2 = this->refKeypoints[i];
descriptors2 = this->refDescriptors[i];
image2= this->referencePics[i];
// 2. Match the two image descriptors
// Construction of the matcher
//cv::Ptr<cv::DescriptorMatcher> matcher = new cv::DescriptorMatcher::create("BruteForceMatcher");
//OPEN CV 2.3 style:
cv::BruteForceMatcher<cv::L2<float> > matcher;
// from image 1 to image 2
// based on k nearest neighbours (with k=2)
std::vector<std::vector<cv::DMatch> > matches1;
matches1.clear();
matcher.knnMatch(descriptors1, descriptors2, matches1, // vector of matches (up to 2 per entry)
2); // return 2 nearest neighbours
// from image 2 to image 1
// based on k nearest neighbours (with k=2)
std::vector<std::vector<cv::DMatch> > matches2;
matches2.clear();
matcher.knnMatch(descriptors2, descriptors1, matches2, // vector of matches (up to 2 per entry)
2); // return 2 nearest neighbours
//std::cout << "Number of matched points 1->2: " << matches1.size() << std::endl;
//std::cout << "Number of matched points 2->1: " << matches2.size() << std::endl;
//cv::waitKey(0);
int stableMatches= 0;
stableMatches = stableMatches+0;
// 3. Remove matches for which NN ratio is > than threshold
if (rTest12) {
// clean image 1 -> image 2 matches
int removed = ratioTest(matches1);
printf("%i", (int)(matches1.size() - removed));
resultText << (int)(matches1.size() - removed);
onScreenText.str(std::string());
onScreenText << "Matches (1->2): " << (matches1.size() - removed);
cv::putText(tmp, onScreenText.str(), cv::Point(((this->allReferences.cols / this->referencePics.size()) * i + 10),15), CV_FONT_HERSHEY_SIMPLEX, 0.50, cv::Scalar(200, 200, 0), 1, CV_AA);
stableMatches = matches1.size() - removed;
featureMatches[0][i]= matches1.size() - removed;
if (rTest21) {
// clean image 2 -> image 1 matches
removed = ratioTest(matches2);
printf("/%i\t", (int)(matches2.size() - removed));
resultText << "/" << (int)(matches2.size() - removed) << " ";
onScreenText.str(std::string());
onScreenText << "Matches (1<-2): " << (matches2.size() - removed);
cv::putText(tmp, onScreenText.str(), cv::Point(((this->allReferences.cols / this->referencePics.size()) * i + 10),35), CV_FONT_HERSHEY_SIMPLEX, 0.50, cv::Scalar(200, 200, 0), 1, CV_AA);
stableMatches = matches2.size() - removed;
featureMatches[1][i]= matches2.size() - removed;
// 4. Remove non-symmetrical matches
if (symTest) {
std::vector<cv::DMatch> symMatches;
symmetryTest(matches1, matches2, symMatches);
std::cout << "Number of matched points (symmetry test): "
<< symMatches.size() << std::endl;
stableMatches = symMatches.size();
featureMatches[1][i]= symMatches.size();
// 5. Validate matches using RANSAC
if (rsacTest) {
cv::Mat fundemental = ransacTest(symMatches, keypoints1,
keypoints2, matches);
stableMatches = matches.size();
featureMatches[1][i]= symMatches.size();
}
}
}
}
// Wenn die Anzahl an Matches beidseitig größer als 15 ist
if ((featureMatches[0][i] > minimumMatches) && (featureMatches[1][i] > minimumMatches)) {
if (((featureMatches[1][i]) + (featureMatches[0][i])) > highestMatch) {
highestMatch= ((featureMatches[1][i]) + (featureMatches[0][i]));
positiveRef= i;
bestKeypoints=keypoints2;
bestMatches= matches2;
info_lastMatch.positiveMatches1 = featureMatches[0][i];
info_lastMatch.positiveMatches2 = featureMatches[1][i];
//cv::waitKey(0);
}
}
}
std::cout << std::endl;
// Now look for highest positive Match!
// TODO: die refPic links und rechts von RefPic[highestMatch] auf Matches überprüfen -> sollten auch Matches haben!!
highestComp= highestMatch;
if (positiveRef > -1) {
std::cout << "The Object was found. Reference picture number " << positiveRef+1 << " gave the best results." << std::endl;
if (this->showWindows) {
cv::drawMatches(image1, keypoints1, // 1st image and its keypoints
this->referencePics[positiveRef], bestKeypoints, // 2nd image and its keypoints
bestMatches, // the matches
matchesMat, // the image produced
cv::Scalar(0, 255, 0)); // color of the lines
onScreenText.str(std::string());
onScreenText << "Ref1 Ref2 Ref3 Ref4 Ref5 Ref6 Ref7 Ref8";
cv::putText(matchesMat, onScreenText.str(), cv::Point(image1.cols/2 - 200, image1.rows/2 +30), CV_FONT_HERSHEY_SIMPLEX, 0.5, cv::Scalar(10, 10, 255), 1, CV_AA);
cv::putText(matchesMat, resultText.str(), cv::Point(image1.cols/2 - 200, image1.rows/2 + 50), CV_FONT_HERSHEY_SIMPLEX, 0.5, cv::Scalar(10, 10, 255), 1, CV_AA);
cv::namedWindow("Features", CV_WINDOW_AUTOSIZE);
cv::imshow("Features", matchesMat);
}
info_lastMatch.processingTime = (ros::Time::now().nsec - startTime.nsec)/1000000;
return true;
}
// "else"
if (this->showWindows && (keypoints1.size() > 0)) {
image1.copyTo(matchesMat);
onScreenText.str(std::string());
onScreenText << "This is not the wanted object!";
cv::putText(matchesMat, onScreenText.str(), cv::Point(image1.cols/2 - 200, image1.rows/2), CV_FONT_HERSHEY_SIMPLEX, 0.8, cv::Scalar(10, 10, 200), 2, CV_AA);
onScreenText.str(std::string());
onScreenText << "Ref1 Ref2 Ref3 Ref4 Ref5 Ref6 Ref7 Ref8";
cv::putText(matchesMat, onScreenText.str(), cv::Point(image1.cols/2 - 200, image1.rows/2 +30), CV_FONT_HERSHEY_SIMPLEX, 0.5, cv::Scalar(10, 10, 200), 1, CV_AA);
cv::putText(matchesMat, resultText.str(), cv::Point(image1.cols/2 - 200, image1.rows/2 + 50), CV_FONT_HERSHEY_SIMPLEX, 0.5, cv::Scalar(10, 10, 200), 1, CV_AA);
cv::namedWindow("Features", CV_WINDOW_AUTOSIZE);
cv::imshow("Features", matchesMat);
}
info_lastMatch.processingTime = (ros::Time::now().nsec - startTime.nsec)/1000000;
return false;
}
/*****************************************************************************
// The knn matching with k = 2
// This code performs the matching and the refinement.
// @paraam query_image: the input image
// @param matches_out: a pointer that stores the output matches. It is necessary for
// pose estimation.
*/
int knn_match(cv::Mat& query_image, std::vector< cv::DMatch> * matches_out)
{
// variabels that keep the query keypoints and query descriptors
std::vector<cv::KeyPoint> keypointsQuery;
cv::Mat descriptorQuery;
// Temporary variables for the matching results
std::vector< std::vector< cv::DMatch> > matches1;
std::vector< std::vector< cv::DMatch> > matches2;
std::vector< std::vector< cv::DMatch> > matches_opt1;
//////////////////////////////////////////////////////////////////////
// 1. Detect the keypoints
// This line detects keypoints in the query image
_detector->detect(query_image, keypointsQuery);
// If keypoints were found, descriptors are extracted.
if(keypointsQuery.size() > 0)
{
// extract descriptors
_extractor->compute( query_image, keypointsQuery, descriptorQuery);
}
//////////////////////////////////////////////////////////////////////////////
// 2. Here we match the descriptors with the database descriptors.
// with k-nearest neighbors with k=2
_matcher.knnMatch(descriptorQuery , matches1, 2);
#ifdef DEBUG_OUT
std::cout << "Found " << matches1.size() << " matching feature descriptors out of " << _matcher.getTrainDescriptors().size() << " database descriptors." << std::endl;
#endif
//////////////////////////////////////////////////////////////////////////////
// 3 Filter the matches.
// Accept only matches (knn with k=2) which belong ot one images
// The database tree within _matcher contains descriptors of all input images.
// We expect that both nearest neighbors must belong to one image.
// Otherwise we can remove the result.
// Along with this, we count which reference image has the highest number of matches.
// At this time, we consinder this image as the searched image.
// we init the variable hit with 0
std::vector<int> hits(_num_ref_images);
for (int i=0; i<_num_ref_images; i++)
{
hits[i] = 0;
}
// the loop runs through all matches and comparees the image indes
// imgIdx. The must be equal otherwise the matches belong to two
// different reference images.
for (int i=0; i<matches1.size(); i++)
{
// The comparison.
if(matches1[i].at(0).imgIdx == matches1[i].at(1).imgIdx)
{
// we keep it
matches_opt1.push_back(matches1[i]);
// and count a hit
hits[matches1[i].at(0).imgIdx]++;
}
}
#ifdef DEBUG_OUT
std::cout << "Optimized " << matches_opt1.size() << " feature descriptors." << std::endl;
#endif
// Now we search for the highest number of hits in our hit array
// The variable max_idx keeps the image id.
// The variable max_value the amount of hits.
int max_idx = -1;
int max_value = 0;
for (int i=0; i<_num_ref_images; i++)
{
#ifdef DEBUG_OUT
std::cout << "for " << i << " : " << hits[i] << std::endl;
#endif
if(hits[i] > max_value)
{
max_value = hits[i];
max_idx = i;
}
}
///////////////////////////////////////////////////////
// 4. The cross-match
// At this time, we test the database agains the query descriptors.
// The variable max_id stores the reference image id. Thus, we test only
// the descriptors that belong to max_idx agains the query descriptors.
_matcher.knnMatch(_descriptorsRefDB[max_idx], descriptorQuery, matches2, 2);
///////////////////////////////////////////////////////
// 5. Refinement; Ratio test
// The ratio test only accept matches which are clear without ambiguity.
// The best hit must be closer to the query descriptors than the second hit.
int removed = ratioTest(matches_opt1);
#ifdef DEBUG_OUT
std::cout << "Removed " << removed << " matched." << std::endl;
#endif
removed = ratioTest(matches2);
#ifdef DEBUG_OUT
std::cout << "Removed " << removed << " matched." << std::endl;
#endif
///////////////////////////////////////////////////////
// 6. Refinement; Symmetry test
// We only accept matches which appear in both knn-matches.
// It should not matter whether we test the database against the query desriptors
// or the query descriptors against the database.
// If we do not find the same solution in both directions, we toss the match.
std::vector<cv::DMatch> symMatches;
symmetryTest( matches_opt1, matches2, symMatches);
#ifdef DEBUG_OUT
std::cout << "Kept " << symMatches.size() << " matches after symetry test test." << std::endl;
#endif
///////////////////////////////////////////////////////
// 7. Refinement; Epipolar constraint
// We perform a Epipolar test using the RANSAC method.
if(symMatches.size() > 25)
{
matches_out->clear();
ransacTest( symMatches, _keypointsRefDB[max_idx], keypointsQuery, *matches_out);
}
#ifdef DEBUG_OUT
std::cout << "Kept " << matches_out->size() << " matches after RANSAC test." << std::endl;
#endif
///////////////////////////////////////////////////////
// 8. Draw this image on screen.
cv::Mat out;
cv::drawMatches(feature_map_database[max_idx]._ref_image , _keypointsRefDB[max_idx], query_image, keypointsQuery, *matches_out, out, cv::Scalar(255,255,255), cv::Scalar(0,0,255));
std::string num_matches_str;
std::strstream conv;
conv << matches_out->size();
conv >> num_matches_str;
std::string text;
text.append( num_matches_str);
text.append("( " + _num_ref_features_in_db_str + " total)");
text.append(" matches were found in reference image ");
text.append( feature_map_database[max_idx]._ref_image_str);
putText(out, text, cvPoint(20,20),
cv::FONT_HERSHEY_COMPLEX_SMALL, 1.0, cvScalar(0,255,255), 1, CV_AA);
cv::imshow("result", out);
if (run_video) cv::waitKey(1);
else cv::waitKey();
// Delete the images
query_image.release();
out.release();
return max_idx;
}
/*****************************************************************************
// This applies a brute force match without a trained datastructure.
// It also calculates the two nearest neigbors.
// @paraam query_image: the input image
// @param matches_out: a pointer that stores the output matches. It is necessary for
// pose estimation.
*/
int brute_force_match(cv::Mat& query_image, std::vector< cv::DMatch> * matches_out)
{
// variabels that keep the query keypoints and query descriptors
std::vector<cv::KeyPoint> keypointsQuery;
cv::Mat descriptorQuery;
// Temporary variables for the matching results
std::vector< std::vector< cv::DMatch> > matches1;
std::vector< std::vector< cv::DMatch> > matches2;
std::vector< std::vector< cv::DMatch> > matches_opt1;
//////////////////////////////////////////////////////////////////////
// 1. Detect the keypoints
// This line detects keypoints in the query image
_detector->detect(query_image, keypointsQuery);
// If keypoints were found, descriptors are extracted.
if(keypointsQuery.size() > 0)
{
// extract descriptors
_extractor->compute( query_image, keypointsQuery, descriptorQuery);
}
#ifdef DEBUG_OUT
std::cout << "Found " << descriptorQuery.size() << " feature descriptors in the image." << std::endl;
#endif
//////////////////////////////////////////////////////////////////////////////
// 2. Here we match the descriptors with all descriptors in the database
// with k-nearest neighbors with k=2
int max_removed = INT_MAX;
int max_id = -1;
for(int i=0; i<_descriptorsRefDB.size(); i++)
{
std::vector< std::vector< cv::DMatch> > matches_temp1;
// Here we match all query descriptors agains all db descriptors and try to find
// matching descriptors
_brute_force_matcher.knnMatch( descriptorQuery, _descriptorsRefDB[i], matches_temp1, 2);
///////////////////////////////////////////////////////
// 3. Refinement; Ratio test
// The ratio test only accept matches which are clear without ambiguity.
// The best hit must be closer to the query descriptors than the second hit.
int removed = ratioTest(matches_temp1);
// We only accept the match with the highest number of hits / the vector with the minimum revmoved features
int num_matches = matches_temp1.size();
if(removed < max_removed)
{
max_removed = removed;
max_id = i;
matches1.clear();
matches1 = matches_temp1;
}
}
#ifdef DEBUG_OUT
std::cout << "Feature map number " << max_id << " has the highest hit with "<< matches1.size() - max_removed << " descriptors." << std::endl;
#endif
std::vector< std::vector< cv::DMatch> > matches_temp2;
// Here we match all query descriptors agains all db descriptors and try to find
// matching descriptors
_brute_force_matcher.knnMatch(_descriptorsRefDB[max_id], descriptorQuery, matches_temp2, 2);
// The ratio test only accept matches which are clear without ambiguity.
// The best hit must be closer to the query descriptors than the second hit.
int removed = ratioTest(matches_temp2);
///////////////////////////////////////////////////////
// 6. Refinement; Symmetry test
// We only accept matches which appear in both knn-matches.
// It should not matter whether we test the database against the query desriptors
// or the query descriptors against the database.
// If we do not find the same solution in both directions, we toss the match.
std::vector<cv::DMatch> symMatches;
symmetryTest( matches1, matches_temp2, symMatches);
#ifdef DEBUG_OUT
std::cout << "Kept " << symMatches.size() << " matches after symetry test test." << std::endl;
#endif
///////////////////////////////////////////////////////
// 7. Refinement; Epipolar constraint
// We perform a Epipolar test using the RANSAC method.
if(symMatches.size() > 25)
{
matches_out->clear();
ransacTest( symMatches, _keypointsRefDB[max_id], keypointsQuery, *matches_out);
}
#ifdef DEBUG_OUT
std::cout << "Kept " << matches_out->size() << " matches after RANSAC test." << std::endl;
#endif
///////////////////////////////////////////////////////
// 8. Draw this image on screen.
cv::Mat out;
cv::drawMatches(feature_map_database[max_id]._ref_image , _keypointsRefDB[max_id], query_image, keypointsQuery, *matches_out, out, cv::Scalar(255,255,255), cv::Scalar(0,0,255));
std::string num_matches_str;
std::strstream conv;
conv << matches_out->size();
conv >> num_matches_str;
std::string text;
text.append( num_matches_str);
text.append("( " + _num_ref_features_in_db_str + " total)");
text.append(" matches were found in reference image ");
text.append( feature_map_database[max_id]._ref_image_str);
putText(out, text, cvPoint(20,20),
cv::FONT_HERSHEY_COMPLEX_SMALL, 1.0, cvScalar(0,255,255), 1, CV_AA);
cv::imshow("result", out);
if (run_video) cv::waitKey(1);
else cv::waitKey();
// Delete the images
query_image.release();
out.release();
return max_id;
}
// Match feature points using symmetry test and RANSAC
// returns fundemental matrix
cv::Mat RobustMatcher::match(cv::Mat &image1,
cv::Mat& image2, // input image
// output matches and keypoints
std::vector<cv::DMatch> &matches, std::vector<cv::KeyPoint> &keypoints1,
std::vector<cv::KeyPoint> &keypoints2) {
// 1a. Detection of the SURF features
helper->detectKeypoints(image1, keypoints1);
helper->detectKeypoints(image2, keypoints2);
// 1b. Extraction of the SURF descriptors
cv::Mat descriptors1, descriptors2;
extractor->compute(image1, keypoints1, descriptors1);
extractor->compute(image2, keypoints2, descriptors2);
//cout << "RobustMatcher: Keypoints 1: " << keypoints1.size() << endl;
//cout << "RobustMatcher: Keypoints 2: " << keypoints2.size() << endl;
// 2. Match the two image descriptors
// Construction of the matcher
cv::BruteForceMatcher<cv::L2<float> > matcher;
// from image 1 to image 2
// based on k neares neighbours (with k=2)
std::vector<std::vector<cv::DMatch> > matches1;
matcher.knnMatch(descriptors1, descriptors2, matches1, // vector of matches (up to 2 per entry)
2); // returns 2 nearest neighbours
// from image 2 to image 1
// based on k nearest neighbours (with k=2)
std::vector<std::vector<cv::DMatch> > matches2;
matcher.knnMatch(descriptors2, descriptors1, matches2, // vector of matches (up to 2 per entry)
2); // return 2 nearest neighbours
//cout << "Matchtes in Bild 2: " << matches1.size() << endl;
// 3. Remove matches for which NN ratio is > than threshold
// clean image 1 -> image 2 matches
int removed = ratioTest(matches1);
//cout << "Ratio; Entfernte Matches Bild 2: " << removed << endl;
//cout << "Matchtes in Bild 1: " << matches2.size() << endl;
// clean image 2 -> image 1 matches
removed = ratioTest(matches2);
//cout << "Ratio; Entfernte Matches Bild 1: " << removed << endl;
// 4. Remove non-symmetrical matches
std::vector<cv::DMatch> symMatches;
symmetryTest(matches1, matches2, symMatches);
//cout << "Symmetrische Matches: " << symMatches.size() << endl;
matches = symMatches;
// 5. Validate matches using RANSAC
cv::Mat fundemental = ransacTest(symMatches, keypoints1, keypoints2,
matches);
// return the found fundemental matrix
//cv::Mat fundemental;
return fundemental;
}
// Match feature points using symmetry test and RANSAC
// Returns number of matched points
cv::Mat RobustMatcher::match(cv::Mat& image1, cv::Mat& image2, // input images
std::vector<cv::DMatch>& matches, // output matches and keypoints
std::vector<cv::KeyPoint>& keypoints1, std::vector<cv::KeyPoint>& keypoints2) {
// 1a. Detection of the SURF features
this->_detector->detect(image1,keypoints1);
this->_detector->detect(image2,keypoints2);
//std::cout << "Number of SURF points (1): " << keypoints1.size() << std::endl;
//std::cout << "Number of SURF points (2): " << keypoints2.size() << std::endl;
// 1b. Extraction of the SURF descriptors
cv::Mat descriptors1, descriptors2;
this->_extractor->compute(image1,keypoints1,descriptors1);
this->_extractor->compute(image2,keypoints2,descriptors2);
matches.clear();
if(keypoints1.empty() || keypoints2.empty()) return cv::Mat();
//std::cout << "descriptor matrix size: " << descriptors1.rows << " by " << descriptors1.cols << std::endl;
// 2. Match the two image descriptors
// Construction of the matcher
cv::BruteForceMatcher<cv::L2<float> > matcher;
// from image 1 to image 2
// based on k nearest neighbours (with k=2)
std::vector<std::vector<cv::DMatch> > matches1;
matcher.knnMatch(descriptors1,descriptors2,
matches1, // vector of matches (up to 2 per entry)
2); // return 2 nearest neighbours
// from image 2 to image 1
// based on k nearest neighbours (with k=2)
std::vector<std::vector<cv::DMatch> > matches2;
matcher.knnMatch(descriptors2,descriptors1,
matches2, // vector of matches (up to 2 per entry)
2); // return 2 nearest neighbours
//std::cout << "Number of matched points 1->2: " << matches1.size() << std::endl;
//std::cout << "Number of matched points 2->1: " << matches2.size() << std::endl;
// 3. Remove matches for which NN ratio is > than threshold
// clean image 1 -> image 2 matches
//int removed = ratioTest(matches1);
//std::cout << "Number of matched points 1->2 (ratio test) : " << matches1.size()-removed << std::endl;
// clean image 2 -> image 1 matches
//removed = ratioTest(matches2);
//std::cout << "Number of matched points 1->2 (ratio test) : " << matches2.size()-removed << std::endl;
// 4. Remove non-symmetrical matches
std::vector<cv::DMatch> symMatches;
symmetryTest(matches1,matches2,symMatches);
//std::cout << "Number of matched points (symmetry test): " << symMatches.size() << std::endl;
// 5. Validate matches using RANSAC
cv::Mat fundamental = ransacTest(symMatches,
keypoints1, keypoints2, matches);
// return the found fundemental matrix
return fundamental;
}
