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#include "precomp.hpp"
#include "opencv2/calib3d/calib3d_c.h"
#include "opencv2/core/cvdef.h"
using namespace cv;
using namespace cv::detail;
namespace {
struct IncDistance
{
IncDistance(std::vector<int> &vdists) : dists(&vdists[0]) {}
void operator ()(const GraphEdge &edge) { dists[edge.to] = dists[edge.from] + 1; }
int* dists;
};
struct CalcRotation
{
CalcRotation(int _num_images, const std::vector<MatchesInfo> &_pairwise_matches, std::vector<CameraParams> &_cameras)
: num_images(_num_images), pairwise_matches(&_pairwise_matches[0]), cameras(&_cameras[0]) {}
void operator ()(const GraphEdge &edge)
{
int pair_idx = edge.from * num_images + edge.to;
Mat_<double> K_from = Mat::eye(3, 3, CV_64F);
K_from(0,0) = cameras[edge.from].focal;
K_from(1,1) = cameras[edge.from].focal * cameras[edge.from].aspect;
K_from(0,2) = cameras[edge.from].ppx;
K_from(1,2) = cameras[edge.from].ppy;
Mat_<double> K_to = Mat::eye(3, 3, CV_64F);
K_to(0,0) = cameras[edge.to].focal;
K_to(1,1) = cameras[edge.to].focal * cameras[edge.to].aspect;
K_to(0,2) = cameras[edge.to].ppx;
K_to(1,2) = cameras[edge.to].ppy;
Mat R = K_from.inv() * pairwise_matches[pair_idx].H.inv() * K_to;
cameras[edge.to].R = cameras[edge.from].R * R;
}
int num_images;
const MatchesInfo* pairwise_matches;
CameraParams* cameras;
};
//////////////////////////////////////////////////////////////////////////////
void calcDeriv(const Mat &err1, const Mat &err2, double h, Mat res)
{
for (int i = 0; i < err1.rows; ++i)
res.at<double>(i, 0) = (err2.at<double>(i, 0) - err1.at<double>(i, 0)) / h;
}
} // namespace
namespace cv {
namespace detail {
bool HomographyBasedEstimator::estimate(
const std::vector<ImageFeatures> &features,
const std::vector<MatchesInfo> &pairwise_matches,
std::vector<CameraParams> &cameras)
{
LOGLN("Estimating rotations...");
#if ENABLE_LOG
int64 t = getTickCount();
#endif
const int num_images = static_cast<int>(features.size());
#if 0
// Robustly estimate focal length from rotating cameras
std::vector<Mat> Hs;
for (int iter = 0; iter < 100; ++iter)
{
int len = 2 + rand()%(pairwise_matches.size() - 1);
std::vector<int> subset;
selectRandomSubset(len, pairwise_matches.size(), subset);
Hs.clear();
for (size_t i = 0; i < subset.size(); ++i)
if (!pairwise_matches[subset[i]].H.empty())
Hs.push_back(pairwise_matches[subset[i]].H);
Mat_<double> K;
if (Hs.size() >= 2)
{
if (calibrateRotatingCamera(Hs, K))
cin.get();
}
}
#endif
if (!is_focals_estimated_)
{
// Estimate focal length and set it for all cameras
std::vector<double> focals;
estimateFocal(features, pairwise_matches, focals);
cameras.assign(num_images, CameraParams());
for (int i = 0; i < num_images; ++i)
cameras[i].focal = focals[i];
}
else
{
for (int i = 0; i < num_images; ++i)
{
cameras[i].ppx -= 0.5 * features[i].img_size.width;
cameras[i].ppy -= 0.5 * features[i].img_size.height;
}
}
// Restore global motion
Graph span_tree;
std::vector<int> span_tree_centers;
findMaxSpanningTree(num_images, pairwise_matches, span_tree, span_tree_centers);
span_tree.walkBreadthFirst(span_tree_centers[0], CalcRotation(num_images, pairwise_matches, cameras));
// As calculations were performed under assumption that p.p. is in image center
for (int i = 0; i < num_images; ++i)
{
cameras[i].ppx += 0.5 * features[i].img_size.width;
cameras[i].ppy += 0.5 * features[i].img_size.height;
}
LOGLN("Estimating rotations, time: " << ((getTickCount() - t) / getTickFrequency()) << " sec");
return true;
}
//////////////////////////////////////////////////////////////////////////////
bool BundleAdjusterBase::estimate(const std::vector<ImageFeatures> &features,
const std::vector<MatchesInfo> &pairwise_matches,
std::vector<CameraParams> &cameras)
{
LOG_CHAT("Bundle adjustment");
#if ENABLE_LOG
int64 t = getTickCount();
#endif
num_images_ = static_cast<int>(features.size());
features_ = &features[0];
pairwise_matches_ = &pairwise_matches[0];
setUpInitialCameraParams(cameras);
// Leave only consistent image pairs
edges_.clear();
for (int i = 0; i < num_images_ - 1; ++i)
{
for (int j = i + 1; j < num_images_; ++j)
{
const MatchesInfo& matches_info = pairwise_matches_[i * num_images_ + j];
if (matches_info.confidence > conf_thresh_)
edges_.push_back(std::make_pair(i, j));
}
}
// Compute number of correspondences
total_num_matches_ = 0;
for (size_t i = 0; i < edges_.size(); ++i)
total_num_matches_ += static_cast<int>(pairwise_matches[edges_[i].first * num_images_ +
edges_[i].second].num_inliers);
CvLevMarq solver(num_images_ * num_params_per_cam_,
total_num_matches_ * num_errs_per_measurement_,
term_criteria_);
Mat err, jac;
CvMat matParams = cam_params_;
cvCopy(&matParams, solver.param);
int iter = 0;
for(;;)
{
const CvMat* _param = 0;
CvMat* _jac = 0;
CvMat* _err = 0;
bool proceed = solver.update(_param, _jac, _err);
cvCopy(_param, &matParams);
if (!proceed || !_err)
break;
if (_jac)
{
calcJacobian(jac);
CvMat tmp = jac;
cvCopy(&tmp, _jac);
}
if (_err)
{
calcError(err);
LOG_CHAT(".");
iter++;
CvMat tmp = err;
cvCopy(&tmp, _err);
}
}
LOGLN_CHAT("");
LOGLN_CHAT("Bundle adjustment, final RMS error: " << std::sqrt(err.dot(err) / total_num_matches_));
LOGLN_CHAT("Bundle adjustment, iterations done: " << iter);
// Check if all camera parameters are valid
bool ok = true;
for (int i = 0; i < cam_params_.rows; ++i)
{
if (cvIsNaN(cam_params_.at<double>(i,0)))
{
ok = false;
break;
}
}
if (!ok)
return false;
obtainRefinedCameraParams(cameras);
// Normalize motion to center image
Graph span_tree;
std::vector<int> span_tree_centers;
findMaxSpanningTree(num_images_, pairwise_matches, span_tree, span_tree_centers);
Mat R_inv = cameras[span_tree_centers[0]].R.inv();
for (int i = 0; i < num_images_; ++i)
cameras[i].R = R_inv * cameras[i].R;
LOGLN_CHAT("Bundle adjustment, time: " << ((getTickCount() - t) / getTickFrequency()) << " sec");
return true;
}
//////////////////////////////////////////////////////////////////////////////
void BundleAdjusterReproj::setUpInitialCameraParams(const std::vector<CameraParams> &cameras)
{
cam_params_.create(num_images_ * 7, 1, CV_64F);
SVD svd;
for (int i = 0; i < num_images_; ++i)
{
cam_params_.at<double>(i * 7, 0) = cameras[i].focal;
cam_params_.at<double>(i * 7 + 1, 0) = cameras[i].ppx;
cam_params_.at<double>(i * 7 + 2, 0) = cameras[i].ppy;
cam_params_.at<double>(i * 7 + 3, 0) = cameras[i].aspect;
svd(cameras[i].R, SVD::FULL_UV);
Mat R = svd.u * svd.vt;
if (determinant(R) < 0)
R *= -1;
Mat rvec;
Rodrigues(R, rvec);
CV_Assert(rvec.type() == CV_32F);
cam_params_.at<double>(i * 7 + 4, 0) = rvec.at<float>(0, 0);
cam_params_.at<double>(i * 7 + 5, 0) = rvec.at<float>(1, 0);
cam_params_.at<double>(i * 7 + 6, 0) = rvec.at<float>(2, 0);
}
}
void BundleAdjusterReproj::obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const
{
for (int i = 0; i < num_images_; ++i)
{
cameras[i].focal = cam_params_.at<double>(i * 7, 0);
cameras[i].ppx = cam_params_.at<double>(i * 7 + 1, 0);
cameras[i].ppy = cam_params_.at<double>(i * 7 + 2, 0);
cameras[i].aspect = cam_params_.at<double>(i * 7 + 3, 0);
Mat rvec(3, 1, CV_64F);
rvec.at<double>(0, 0) = cam_params_.at<double>(i * 7 + 4, 0);
rvec.at<double>(1, 0) = cam_params_.at<double>(i * 7 + 5, 0);
rvec.at<double>(2, 0) = cam_params_.at<double>(i * 7 + 6, 0);
Rodrigues(rvec, cameras[i].R);
Mat tmp;
cameras[i].R.convertTo(tmp, CV_32F);
cameras[i].R = tmp;
}
}
void BundleAdjusterReproj::calcError(Mat &err)
{
err.create(total_num_matches_ * 2, 1, CV_64F);
int match_idx = 0;
for (size_t edge_idx = 0; edge_idx < edges_.size(); ++edge_idx)
{
int i = edges_[edge_idx].first;
int j = edges_[edge_idx].second;
double f1 = cam_params_.at<double>(i * 7, 0);
double f2 = cam_params_.at<double>(j * 7, 0);
double ppx1 = cam_params_.at<double>(i * 7 + 1, 0);
double ppx2 = cam_params_.at<double>(j * 7 + 1, 0);
double ppy1 = cam_params_.at<double>(i * 7 + 2, 0);
double ppy2 = cam_params_.at<double>(j * 7 + 2, 0);
double a1 = cam_params_.at<double>(i * 7 + 3, 0);
double a2 = cam_params_.at<double>(j * 7 + 3, 0);
double R1[9];
Mat R1_(3, 3, CV_64F, R1);
Mat rvec(3, 1, CV_64F);
rvec.at<double>(0, 0) = cam_params_.at<double>(i * 7 + 4, 0);
rvec.at<double>(1, 0) = cam_params_.at<double>(i * 7 + 5, 0);
rvec.at<double>(2, 0) = cam_params_.at<double>(i * 7 + 6, 0);
Rodrigues(rvec, R1_);
double R2[9];
Mat R2_(3, 3, CV_64F, R2);
rvec.at<double>(0, 0) = cam_params_.at<double>(j * 7 + 4, 0);
rvec.at<double>(1, 0) = cam_params_.at<double>(j * 7 + 5, 0);
rvec.at<double>(2, 0) = cam_params_.at<double>(j * 7 + 6, 0);
Rodrigues(rvec, R2_);
const ImageFeatures& features1 = features_[i];
const ImageFeatures& features2 = features_[j];
const MatchesInfo& matches_info = pairwise_matches_[i * num_images_ + j];
Mat_<double> K1 = Mat::eye(3, 3, CV_64F);
K1(0,0) = f1; K1(0,2) = ppx1;
K1(1,1) = f1*a1; K1(1,2) = ppy1;
Mat_<double> K2 = Mat::eye(3, 3, CV_64F);
K2(0,0) = f2; K2(0,2) = ppx2;
K2(1,1) = f2*a2; K2(1,2) = ppy2;
Mat_<double> H = K2 * R2_.inv() * R1_ * K1.inv();
for (size_t k = 0; k < matches_info.matches.size(); ++k)
{
if (!matches_info.inliers_mask[k])
continue;
const DMatch& m = matches_info.matches[k];
Point2f p1 = features1.keypoints[m.queryIdx].pt;
Point2f p2 = features2.keypoints[m.trainIdx].pt;
double x = H(0,0)*p1.x + H(0,1)*p1.y + H(0,2);
double y = H(1,0)*p1.x + H(1,1)*p1.y + H(1,2);
double z = H(2,0)*p1.x + H(2,1)*p1.y + H(2,2);
err.at<double>(2 * match_idx, 0) = p2.x - x/z;
err.at<double>(2 * match_idx + 1, 0) = p2.y - y/z;
match_idx++;
}
}
}
void BundleAdjusterReproj::calcJacobian(Mat &jac)
{
jac.create(total_num_matches_ * 2, num_images_ * 7, CV_64F);
jac.setTo(0);
double val;
const double step = 1e-4;
for (int i = 0; i < num_images_; ++i)
{
if (refinement_mask_.at<uchar>(0, 0))
{
val = cam_params_.at<double>(i * 7, 0);
cam_params_.at<double>(i * 7, 0) = val - step;
calcError(err1_);
cam_params_.at<double>(i * 7, 0) = val + step;
calcError(err2_);
calcDeriv(err1_, err2_, 2 * step, jac.col(i * 7));
cam_params_.at<double>(i * 7, 0) = val;
}
if (refinement_mask_.at<uchar>(0, 2))
{
val = cam_params_.at<double>(i * 7 + 1, 0);
cam_params_.at<double>(i * 7 + 1, 0) = val - step;
calcError(err1_);
cam_params_.at<double>(i * 7 + 1, 0) = val + step;
calcError(err2_);
calcDeriv(err1_, err2_, 2 * step, jac.col(i * 7 + 1));
cam_params_.at<double>(i * 7 + 1, 0) = val;
}
if (refinement_mask_.at<uchar>(1, 2))
{
val = cam_params_.at<double>(i * 7 + 2, 0);
cam_params_.at<double>(i * 7 + 2, 0) = val - step;
calcError(err1_);
cam_params_.at<double>(i * 7 + 2, 0) = val + step;
calcError(err2_);
calcDeriv(err1_, err2_, 2 * step, jac.col(i * 7 + 2));
cam_params_.at<double>(i * 7 + 2, 0) = val;
}
if (refinement_mask_.at<uchar>(1, 1))
{
val = cam_params_.at<double>(i * 7 + 3, 0);
cam_params_.at<double>(i * 7 + 3, 0) = val - step;
calcError(err1_);
cam_params_.at<double>(i * 7 + 3, 0) = val + step;
calcError(err2_);
calcDeriv(err1_, err2_, 2 * step, jac.col(i * 7 + 3));
cam_params_.at<double>(i * 7 + 3, 0) = val;
}
for (int j = 4; j < 7; ++j)
{
val = cam_params_.at<double>(i * 7 + j, 0);
cam_params_.at<double>(i * 7 + j, 0) = val - step;
calcError(err1_);
cam_params_.at<double>(i * 7 + j, 0) = val + step;
calcError(err2_);
calcDeriv(err1_, err2_, 2 * step, jac.col(i * 7 + j));
cam_params_.at<double>(i * 7 + j, 0) = val;
}
}
}
//////////////////////////////////////////////////////////////////////////////
void BundleAdjusterRay::setUpInitialCameraParams(const std::vector<CameraParams> &cameras)
{
cam_params_.create(num_images_ * 4, 1, CV_64F);
SVD svd;
for (int i = 0; i < num_images_; ++i)
{
cam_params_.at<double>(i * 4, 0) = cameras[i].focal;
svd(cameras[i].R, SVD::FULL_UV);
Mat R = svd.u * svd.vt;
if (determinant(R) < 0)
R *= -1;
Mat rvec;
Rodrigues(R, rvec);
CV_Assert(rvec.type() == CV_32F);
cam_params_.at<double>(i * 4 + 1, 0) = rvec.at<float>(0, 0);
cam_params_.at<double>(i * 4 + 2, 0) = rvec.at<float>(1, 0);
cam_params_.at<double>(i * 4 + 3, 0) = rvec.at<float>(2, 0);
}
}
void BundleAdjusterRay::obtainRefinedCameraParams(std::vector<CameraParams> &cameras) const
{
for (int i = 0; i < num_images_; ++i)
{
cameras[i].focal = cam_params_.at<double>(i * 4, 0);
Mat rvec(3, 1, CV_64F);
rvec.at<double>(0, 0) = cam_params_.at<double>(i * 4 + 1, 0);
rvec.at<double>(1, 0) = cam_params_.at<double>(i * 4 + 2, 0);
rvec.at<double>(2, 0) = cam_params_.at<double>(i * 4 + 3, 0);
Rodrigues(rvec, cameras[i].R);
Mat tmp;
cameras[i].R.convertTo(tmp, CV_32F);
cameras[i].R = tmp;
}
}
void BundleAdjusterRay::calcError(Mat &err)
{
err.create(total_num_matches_ * 3, 1, CV_64F);
int match_idx = 0;
for (size_t edge_idx = 0; edge_idx < edges_.size(); ++edge_idx)
{
int i = edges_[edge_idx].first;
int j = edges_[edge_idx].second;
double f1 = cam_params_.at<double>(i * 4, 0);
double f2 = cam_params_.at<double>(j * 4, 0);
double R1[9];
Mat R1_(3, 3, CV_64F, R1);
Mat rvec(3, 1, CV_64F);
rvec.at<double>(0, 0) = cam_params_.at<double>(i * 4 + 1, 0);
rvec.at<double>(1, 0) = cam_params_.at<double>(i * 4 + 2, 0);
rvec.at<double>(2, 0) = cam_params_.at<double>(i * 4 + 3, 0);
Rodrigues(rvec, R1_);
double R2[9];
Mat R2_(3, 3, CV_64F, R2);
rvec.at<double>(0, 0) = cam_params_.at<double>(j * 4 + 1, 0);
rvec.at<double>(1, 0) = cam_params_.at<double>(j * 4 + 2, 0);
rvec.at<double>(2, 0) = cam_params_.at<double>(j * 4 + 3, 0);
Rodrigues(rvec, R2_);
const ImageFeatures& features1 = features_[i];
const ImageFeatures& features2 = features_[j];
const MatchesInfo& matches_info = pairwise_matches_[i * num_images_ + j];
Mat_<double> K1 = Mat::eye(3, 3, CV_64F);
K1(0,0) = f1; K1(0,2) = features1.img_size.width * 0.5;
K1(1,1) = f1; K1(1,2) = features1.img_size.height * 0.5;
Mat_<double> K2 = Mat::eye(3, 3, CV_64F);
K2(0,0) = f2; K2(0,2) = features2.img_size.width * 0.5;
K2(1,1) = f2; K2(1,2) = features2.img_size.height * 0.5;
Mat_<double> H1 = R1_ * K1.inv();
Mat_<double> H2 = R2_ * K2.inv();
for (size_t k = 0; k < matches_info.matches.size(); ++k)
{
if (!matches_info.inliers_mask[k])
continue;
const DMatch& m = matches_info.matches[k];
Point2f p1 = features1.keypoints[m.queryIdx].pt;
double x1 = H1(0,0)*p1.x + H1(0,1)*p1.y + H1(0,2);
double y1 = H1(1,0)*p1.x + H1(1,1)*p1.y + H1(1,2);
double z1 = H1(2,0)*p1.x + H1(2,1)*p1.y + H1(2,2);
double len = std::sqrt(x1*x1 + y1*y1 + z1*z1);
x1 /= len; y1 /= len; z1 /= len;
Point2f p2 = features2.keypoints[m.trainIdx].pt;
double x2 = H2(0,0)*p2.x + H2(0,1)*p2.y + H2(0,2);
double y2 = H2(1,0)*p2.x + H2(1,1)*p2.y + H2(1,2);
double z2 = H2(2,0)*p2.x + H2(2,1)*p2.y + H2(2,2);
len = std::sqrt(x2*x2 + y2*y2 + z2*z2);
x2 /= len; y2 /= len; z2 /= len;
double mult = std::sqrt(f1 * f2);
err.at<double>(3 * match_idx, 0) = mult * (x1 - x2);
err.at<double>(3 * match_idx + 1, 0) = mult * (y1 - y2);
err.at<double>(3 * match_idx + 2, 0) = mult * (z1 - z2);
match_idx++;
}
}
}
void BundleAdjusterRay::calcJacobian(Mat &jac)
{
jac.create(total_num_matches_ * 3, num_images_ * 4, CV_64F);
double val;
const double step = 1e-3;
for (int i = 0; i < num_images_; ++i)
{
for (int j = 0; j < 4; ++j)
{
val = cam_params_.at<double>(i * 4 + j, 0);
cam_params_.at<double>(i * 4 + j, 0) = val - step;
calcError(err1_);
cam_params_.at<double>(i * 4 + j, 0) = val + step;
calcError(err2_);
calcDeriv(err1_, err2_, 2 * step, jac.col(i * 4 + j));
cam_params_.at<double>(i * 4 + j, 0) = val;
}
}
}
//////////////////////////////////////////////////////////////////////////////
void waveCorrect(std::vector<Mat> &rmats, WaveCorrectKind kind)
{
LOGLN("Wave correcting...");
#if ENABLE_LOG
int64 t = getTickCount();
#endif
if (rmats.size() <= 1)
{
LOGLN("Wave correcting, time: " << ((getTickCount() - t) / getTickFrequency()) << " sec");
return;
}
Mat moment = Mat::zeros(3, 3, CV_32F);
for (size_t i = 0; i < rmats.size(); ++i)
{
Mat col = rmats[i].col(0);
moment += col * col.t();
}
Mat eigen_vals, eigen_vecs;
eigen(moment, eigen_vals, eigen_vecs);
Mat rg1;
if (kind == WAVE_CORRECT_HORIZ)
rg1 = eigen_vecs.row(2).t();
else if (kind == WAVE_CORRECT_VERT)
rg1 = eigen_vecs.row(0).t();
else
CV_Error(CV_StsBadArg, "unsupported kind of wave correction");
Mat img_k = Mat::zeros(3, 1, CV_32F);
for (size_t i = 0; i < rmats.size(); ++i)
img_k += rmats[i].col(2);
Mat rg0 = rg1.cross(img_k);
double rg0_norm = norm(rg0);
if( rg0_norm <= DBL_MIN )
{
return;
}
rg0 /= rg0_norm;
Mat rg2 = rg0.cross(rg1);
double conf = 0;
if (kind == WAVE_CORRECT_HORIZ)
{
for (size_t i = 0; i < rmats.size(); ++i)
conf += rg0.dot(rmats[i].col(0));
if (conf < 0)
{
rg0 *= -1;
rg1 *= -1;
}
}
else if (kind == WAVE_CORRECT_VERT)
{
for (size_t i = 0; i < rmats.size(); ++i)
conf -= rg1.dot(rmats[i].col(0));
if (conf < 0)
{
rg0 *= -1;
rg1 *= -1;
}
}
Mat R = Mat::zeros(3, 3, CV_32F);
Mat tmp = R.row(0);
Mat(rg0.t()).copyTo(tmp);
tmp = R.row(1);
Mat(rg1.t()).copyTo(tmp);
tmp = R.row(2);
Mat(rg2.t()).copyTo(tmp);
for (size_t i = 0; i < rmats.size(); ++i)
rmats[i] = R * rmats[i];
LOGLN("Wave correcting, time: " << ((getTickCount() - t) / getTickFrequency()) << " sec");
}
//////////////////////////////////////////////////////////////////////////////
String matchesGraphAsString(std::vector<String> &pathes, std::vector<MatchesInfo> &pairwise_matches,
float conf_threshold)
{
std::stringstream str;
str << "graph matches_graph{\n";
const int num_images = static_cast<int>(pathes.size());
std::set<std::pair<int,int> > span_tree_edges;
DisjointSets comps(num_images);
for (int i = 0; i < num_images; ++i)
{
for (int j = 0; j < num_images; ++j)
{
if (pairwise_matches[i*num_images + j].confidence < conf_threshold)
continue;
int comp1 = comps.findSetByElem(i);
int comp2 = comps.findSetByElem(j);
if (comp1 != comp2)
{
comps.mergeSets(comp1, comp2);
span_tree_edges.insert(std::make_pair(i, j));
}
}
}
for (std::set<std::pair<int,int> >::const_iterator itr = span_tree_edges.begin();
itr != span_tree_edges.end(); ++itr)
{
std::pair<int,int> edge = *itr;
if (span_tree_edges.find(edge) != span_tree_edges.end())
{
String name_src = pathes[edge.first];
size_t prefix_len = name_src.find_last_of("/\\");
if (prefix_len != String::npos) prefix_len++; else prefix_len = 0;
name_src = name_src.substr(prefix_len, name_src.size() - prefix_len);
String name_dst = pathes[edge.second];
prefix_len = name_dst.find_last_of("/\\");
if (prefix_len != String::npos) prefix_len++; else prefix_len = 0;
name_dst = name_dst.substr(prefix_len, name_dst.size() - prefix_len);
int pos = edge.first*num_images + edge.second;
str << "\"" << name_src.c_str() << "\" -- \"" << name_dst.c_str() << "\""
<< "[label=\"Nm=" << pairwise_matches[pos].matches.size()
<< ", Ni=" << pairwise_matches[pos].num_inliers
<< ", C=" << pairwise_matches[pos].confidence << "\"];\n";
}
}
for (size_t i = 0; i < comps.size.size(); ++i)
{
if (comps.size[comps.findSetByElem((int)i)] == 1)
{
String name = pathes[i];
size_t prefix_len = name.find_last_of("/\\");
if (prefix_len != String::npos) prefix_len++; else prefix_len = 0;
name = name.substr(prefix_len, name.size() - prefix_len);
str << "\"" << name.c_str() << "\";\n";
}
}
str << "}";
return str.str().c_str();
}
std::vector<int> leaveBiggestComponent(std::vector<ImageFeatures> &features, std::vector<MatchesInfo> &pairwise_matches,
float conf_threshold)
{
const int num_images = static_cast<int>(features.size());
DisjointSets comps(num_images);
for (int i = 0; i < num_images; ++i)
{
for (int j = 0; j < num_images; ++j)
{
if (pairwise_matches[i*num_images + j].confidence < conf_threshold)
continue;
int comp1 = comps.findSetByElem(i);
int comp2 = comps.findSetByElem(j);
if (comp1 != comp2)
comps.mergeSets(comp1, comp2);
}
}
int max_comp = static_cast<int>(std::max_element(comps.size.begin(), comps.size.end()) - comps.size.begin());
std::vector<int> indices;
std::vector<int> indices_removed;
for (int i = 0; i < num_images; ++i)
if (comps.findSetByElem(i) == max_comp)
indices.push_back(i);
else
indices_removed.push_back(i);
std::vector<ImageFeatures> features_subset;
std::vector<MatchesInfo> pairwise_matches_subset;
for (size_t i = 0; i < indices.size(); ++i)
{
features_subset.push_back(features[indices[i]]);
for (size_t j = 0; j < indices.size(); ++j)
{
pairwise_matches_subset.push_back(pairwise_matches[indices[i]*num_images + indices[j]]);
pairwise_matches_subset.back().src_img_idx = static_cast<int>(i);
pairwise_matches_subset.back().dst_img_idx = static_cast<int>(j);
}
}
if (static_cast<int>(features_subset.size()) == num_images)
return indices;
LOG("Removed some images, because can't match them or there are too similar images: (");
LOG(indices_removed[0] + 1);
for (size_t i = 1; i < indices_removed.size(); ++i)
LOG(", " << indices_removed[i]+1);
LOGLN(").");
LOGLN("Try to decrease the match confidence threshold and/or check if you're stitching duplicates.");
features = features_subset;
pairwise_matches = pairwise_matches_subset;
return indices;
}
void findMaxSpanningTree(int num_images, const std::vector<MatchesInfo> &pairwise_matches,
Graph &span_tree, std::vector<int> ¢ers)
{
Graph graph(num_images);
std::vector<GraphEdge> edges;
// Construct images graph and remember its edges
for (int i = 0; i < num_images; ++i)
{
for (int j = 0; j < num_images; ++j)
{
if (pairwise_matches[i * num_images + j].H.empty())
continue;
float conf = static_cast<float>(pairwise_matches[i * num_images + j].num_inliers);
graph.addEdge(i, j, conf);
edges.push_back(GraphEdge(i, j, conf));
}
}
DisjointSets comps(num_images);
span_tree.create(num_images);
std::vector<int> span_tree_powers(num_images, 0);
// Find maximum spanning tree
sort(edges.begin(), edges.end(), std::greater<GraphEdge>());
for (size_t i = 0; i < edges.size(); ++i)
{
int comp1 = comps.findSetByElem(edges[i].from);
int comp2 = comps.findSetByElem(edges[i].to);
if (comp1 != comp2)
{
comps.mergeSets(comp1, comp2);
span_tree.addEdge(edges[i].from, edges[i].to, edges[i].weight);
span_tree.addEdge(edges[i].to, edges[i].from, edges[i].weight);
span_tree_powers[edges[i].from]++;
span_tree_powers[edges[i].to]++;
}
}
// Find spanning tree leafs
std::vector<int> span_tree_leafs;
for (int i = 0; i < num_images; ++i)
if (span_tree_powers[i] == 1)
span_tree_leafs.push_back(i);
// Find maximum distance from each spanning tree vertex
std::vector<int> max_dists(num_images, 0);
std::vector<int> cur_dists;
for (size_t i = 0; i < span_tree_leafs.size(); ++i)
{
cur_dists.assign(num_images, 0);
span_tree.walkBreadthFirst(span_tree_leafs[i], IncDistance(cur_dists));
for (int j = 0; j < num_images; ++j)
max_dists[j] = std::max(max_dists[j], cur_dists[j]);
}
// Find min-max distance
int min_max_dist = max_dists[0];
for (int i = 1; i < num_images; ++i)
if (min_max_dist > max_dists[i])
min_max_dist = max_dists[i];
// Find spanning tree centers
centers.clear();
for (int i = 0; i < num_images; ++i)
if (max_dists[i] == min_max_dist)
centers.push_back(i);
CV_Assert(centers.size() > 0 && centers.size() <= 2);
}
} // namespace detail
} // namespace cv