opencv/modules/stitching/src/matchers.cpp

600 lines
22 KiB
C++

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#include "precomp.hpp"
using namespace std;
using namespace cv;
using namespace cv::detail;
#ifndef ANDROID
using namespace cv::gpu;
#endif
namespace {
struct DistIdxPair
{
bool operator<(const DistIdxPair &other) const { return dist < other.dist; }
double dist;
int idx;
};
struct MatchPairsBody
{
MatchPairsBody(const MatchPairsBody& other)
: matcher(other.matcher), features(other.features),
pairwise_matches(other.pairwise_matches), near_pairs(other.near_pairs) {}
MatchPairsBody(FeaturesMatcher &matcher, const vector<ImageFeatures> &features,
vector<MatchesInfo> &pairwise_matches, vector<pair<int,int> > &near_pairs)
: matcher(matcher), features(features),
pairwise_matches(pairwise_matches), near_pairs(near_pairs) {}
void operator ()(const BlockedRange &r) const
{
const int num_images = static_cast<int>(features.size());
for (int i = r.begin(); i < r.end(); ++i)
{
int from = near_pairs[i].first;
int to = near_pairs[i].second;
int pair_idx = from*num_images + to;
matcher(features[from], features[to], pairwise_matches[pair_idx]);
pairwise_matches[pair_idx].src_img_idx = from;
pairwise_matches[pair_idx].dst_img_idx = to;
size_t dual_pair_idx = to*num_images + from;
pairwise_matches[dual_pair_idx] = pairwise_matches[pair_idx];
pairwise_matches[dual_pair_idx].src_img_idx = to;
pairwise_matches[dual_pair_idx].dst_img_idx = from;
if (!pairwise_matches[pair_idx].H.empty())
pairwise_matches[dual_pair_idx].H = pairwise_matches[pair_idx].H.inv();
for (size_t j = 0; j < pairwise_matches[dual_pair_idx].matches.size(); ++j)
std::swap(pairwise_matches[dual_pair_idx].matches[j].queryIdx,
pairwise_matches[dual_pair_idx].matches[j].trainIdx);
LOG(".");
}
}
FeaturesMatcher &matcher;
const vector<ImageFeatures> &features;
vector<MatchesInfo> &pairwise_matches;
vector<pair<int,int> > &near_pairs;
private:
void operator =(const MatchPairsBody&);
};
//////////////////////////////////////////////////////////////////////////////
typedef set<pair<int,int> > MatchesSet;
// These two classes are aimed to find features matches only, not to
// estimate homography
class CpuMatcher : public FeaturesMatcher
{
public:
CpuMatcher(float match_conf) : FeaturesMatcher(true), match_conf_(match_conf) {}
void match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info);
private:
float match_conf_;
};
#ifndef ANDROID
class GpuMatcher : public FeaturesMatcher
{
public:
GpuMatcher(float match_conf) : match_conf_(match_conf) {}
void match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info);
void collectGarbage();
private:
float match_conf_;
GpuMat descriptors1_, descriptors2_;
GpuMat train_idx_, distance_, all_dist_;
vector< vector<DMatch> > pair_matches;
};
#endif
void CpuMatcher::match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info)
{
CV_Assert(features1.descriptors.type() == features2.descriptors.type());
CV_Assert(features2.descriptors.depth() == CV_8U || features2.descriptors.depth() == CV_32F);
#ifdef HAVE_TEGRA_OPTIMIZATION
if (tegra::match2nearest(features1, features2, matches_info, match_conf_))
return;
#endif
matches_info.matches.clear();
Ptr<flann::IndexParams> indexParams = new flann::KDTreeIndexParams();
Ptr<flann::SearchParams> searchParams = new flann::SearchParams();
if (features2.descriptors.depth() == CV_8U)
{
indexParams->setAlgorithm(cvflann::FLANN_INDEX_LSH);
searchParams->setAlgorithm(cvflann::FLANN_INDEX_LSH);
}
FlannBasedMatcher matcher(indexParams, searchParams);
vector< vector<DMatch> > pair_matches;
MatchesSet matches;
// Find 1->2 matches
matcher.knnMatch(features1.descriptors, features2.descriptors, pair_matches, 2);
for (size_t i = 0; i < pair_matches.size(); ++i)
{
if (pair_matches[i].size() < 2)
continue;
const DMatch& m0 = pair_matches[i][0];
const DMatch& m1 = pair_matches[i][1];
if (m0.distance < (1.f - match_conf_) * m1.distance)
{
matches_info.matches.push_back(m0);
matches.insert(make_pair(m0.queryIdx, m0.trainIdx));
}
}
LOG("\n1->2 matches: " << matches_info.matches.size() << endl);
// Find 2->1 matches
pair_matches.clear();
matcher.knnMatch(features2.descriptors, features1.descriptors, pair_matches, 2);
for (size_t i = 0; i < pair_matches.size(); ++i)
{
if (pair_matches[i].size() < 2)
continue;
const DMatch& m0 = pair_matches[i][0];
const DMatch& m1 = pair_matches[i][1];
if (m0.distance < (1.f - match_conf_) * m1.distance)
if (matches.find(make_pair(m0.trainIdx, m0.queryIdx)) == matches.end())
matches_info.matches.push_back(DMatch(m0.trainIdx, m0.queryIdx, m0.distance));
}
LOG("1->2 & 2->1 matches: " << matches_info.matches.size() << endl);
}
#ifndef ANDROID
void GpuMatcher::match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info)
{
matches_info.matches.clear();
ensureSizeIsEnough(features1.descriptors.size(), features1.descriptors.type(), descriptors1_);
ensureSizeIsEnough(features2.descriptors.size(), features2.descriptors.type(), descriptors2_);
descriptors1_.upload(features1.descriptors);
descriptors2_.upload(features2.descriptors);
BruteForceMatcher_GPU< L2<float> > matcher;
MatchesSet matches;
// Find 1->2 matches
pair_matches.clear();
matcher.knnMatchSingle(descriptors1_, descriptors2_, train_idx_, distance_, all_dist_, 2);
matcher.knnMatchDownload(train_idx_, distance_, pair_matches);
for (size_t i = 0; i < pair_matches.size(); ++i)
{
if (pair_matches[i].size() < 2)
continue;
const DMatch& m0 = pair_matches[i][0];
const DMatch& m1 = pair_matches[i][1];
if (m0.distance < (1.f - match_conf_) * m1.distance)
{
matches_info.matches.push_back(m0);
matches.insert(make_pair(m0.queryIdx, m0.trainIdx));
}
}
// Find 2->1 matches
pair_matches.clear();
matcher.knnMatchSingle(descriptors2_, descriptors1_, train_idx_, distance_, all_dist_, 2);
matcher.knnMatchDownload(train_idx_, distance_, pair_matches);
for (size_t i = 0; i < pair_matches.size(); ++i)
{
if (pair_matches[i].size() < 2)
continue;
const DMatch& m0 = pair_matches[i][0];
const DMatch& m1 = pair_matches[i][1];
if (m0.distance < (1.f - match_conf_) * m1.distance)
if (matches.find(make_pair(m0.trainIdx, m0.queryIdx)) == matches.end())
matches_info.matches.push_back(DMatch(m0.trainIdx, m0.queryIdx, m0.distance));
}
}
void GpuMatcher::collectGarbage()
{
descriptors1_.release();
descriptors2_.release();
train_idx_.release();
distance_.release();
all_dist_.release();
vector< vector<DMatch> >().swap(pair_matches);
}
#endif
} // namespace
namespace cv {
namespace detail {
void FeaturesFinder::operator ()(const Mat &image, ImageFeatures &features)
{
find(image, features);
features.img_size = image.size();
}
void FeaturesFinder::operator ()(const Mat &image, ImageFeatures &features, const vector<Rect> &rois)
{
vector<ImageFeatures> roi_features(rois.size());
size_t total_kps_count = 0;
int total_descriptors_height = 0;
for (size_t i = 0; i < rois.size(); ++i)
{
find(image(rois[i]), roi_features[i]);
total_kps_count += roi_features[i].keypoints.size();
total_descriptors_height += roi_features[i].descriptors.rows;
}
features.img_size = image.size();
features.keypoints.resize(total_kps_count);
features.descriptors.create(total_descriptors_height,
roi_features[0].descriptors.cols,
roi_features[0].descriptors.type());
int kp_idx = 0;
int descr_offset = 0;
for (size_t i = 0; i < rois.size(); ++i)
{
for (size_t j = 0; j < roi_features[i].keypoints.size(); ++j, ++kp_idx)
{
features.keypoints[kp_idx] = roi_features[i].keypoints[j];
features.keypoints[kp_idx].pt.x += (float)rois[i].x;
features.keypoints[kp_idx].pt.y += (float)rois[i].y;
}
Mat subdescr = features.descriptors.rowRange(
descr_offset, descr_offset + roi_features[i].descriptors.rows);
roi_features[i].descriptors.copyTo(subdescr);
descr_offset += roi_features[i].descriptors.rows;
}
}
SurfFeaturesFinder::SurfFeaturesFinder(double hess_thresh, int num_octaves, int num_layers,
int num_octaves_descr, int num_layers_descr)
{
if (num_octaves_descr == num_octaves && num_layers_descr == num_layers)
{
surf = new SURF(hess_thresh, num_octaves, num_layers);
}
else
{
detector_ = new SurfFeatureDetector(hess_thresh, num_octaves, num_layers);
extractor_ = new SurfDescriptorExtractor(num_octaves_descr, num_layers_descr);
}
}
void SurfFeaturesFinder::find(const Mat &image, ImageFeatures &features)
{
Mat gray_image;
CV_Assert(image.type() == CV_8UC3);
cvtColor(image, gray_image, CV_BGR2GRAY);
if (surf == 0)
{
detector_->detect(gray_image, features.keypoints);
extractor_->compute(gray_image, features.keypoints, features.descriptors);
}
else
{
vector<float> descriptors;
(*surf)(gray_image, Mat(), features.keypoints, descriptors);
features.descriptors = Mat(descriptors, true).reshape(1, (int)features.keypoints.size());
}
}
OrbFeaturesFinder::OrbFeaturesFinder(Size _grid_size, size_t n_features, const ORB::CommonParams & detector_params)
{
grid_size = _grid_size;
orb = new ORB(n_features * (99 + grid_size.area())/100/grid_size.area(), detector_params);
}
void OrbFeaturesFinder::find(const Mat &image, ImageFeatures &features)
{
Mat gray_image;
CV_Assert(image.type() == CV_8UC3);
cvtColor(image, gray_image, CV_BGR2GRAY);
if (grid_size.area() == 1)
(*orb)(gray_image, Mat(), features.keypoints, features.descriptors);
else
{
features.keypoints.clear();
features.descriptors.release();
std::vector<KeyPoint> points;
Mat descriptors;
for (int r = 0; r < grid_size.height; ++r)
for (int c = 0; c < grid_size.width; ++c)
{
int xl = c * gray_image.cols / grid_size.width;
int yl = r * gray_image.rows / grid_size.height;
int xr = (c+1) * gray_image.cols / grid_size.width;
int yr = (r+1) * gray_image.rows / grid_size.height;
LOGLN("OrbFeaturesFinder::find: gray_image.empty=" << (gray_image.empty()?"true":"false") << ", "
<< " gray_image.size()=(" << gray_image.size().width << "x" << gray_image.size().height << "), "
<< " yl=" << yl << ", yr=" << yr << ", "
<< " xl=" << xl << ", xr=" << xr << ", gray_image.data=" << ((size_t)gray_image.data) << ", "
<< "gray_image.dims=" << gray_image.dims << "\n");
Mat gray_image_part=gray_image(Range(yl, yr), Range(xl, xr));
LOGLN("OrbFeaturesFinder::find: gray_image_part.empty=" << (gray_image_part.empty()?"true":"false") << ", "
<< " gray_image_part.size()=(" << gray_image_part.size().width << "x" << gray_image_part.size().height << "), "
<< " gray_image_part.dims=" << gray_image_part.dims << ", "
<< " gray_image_part.data=" << ((size_t)gray_image_part.data) << "\n");
(*orb)(gray_image_part, Mat(), points, descriptors);
features.keypoints.reserve(features.keypoints.size() + points.size());
for (std::vector<KeyPoint>::iterator kp = points.begin(); kp != points.end(); ++kp)
{
kp->pt.x += xl;
kp->pt.y += yl;
features.keypoints.push_back(*kp);
}
features.descriptors.push_back(descriptors);
}
}
}
#ifndef ANDROID
SurfFeaturesFinderGpu::SurfFeaturesFinderGpu(double hess_thresh, int num_octaves, int num_layers,
int num_octaves_descr, int num_layers_descr)
{
surf_.keypointsRatio = 0.1f;
surf_.hessianThreshold = hess_thresh;
surf_.extended = false;
num_octaves_ = num_octaves;
num_layers_ = num_layers;
num_octaves_descr_ = num_octaves_descr;
num_layers_descr_ = num_layers_descr;
}
void SurfFeaturesFinderGpu::find(const Mat &image, ImageFeatures &features)
{
CV_Assert(image.depth() == CV_8U);
ensureSizeIsEnough(image.size(), image.type(), image_);
image_.upload(image);
ensureSizeIsEnough(image.size(), CV_8UC1, gray_image_);
cvtColor(image_, gray_image_, CV_BGR2GRAY);
surf_.nOctaves = num_octaves_;
surf_.nOctaveLayers = num_layers_;
surf_.upright = false;
surf_(gray_image_, GpuMat(), keypoints_);
surf_.nOctaves = num_octaves_descr_;
surf_.nOctaveLayers = num_layers_descr_;
surf_.upright = true;
surf_(gray_image_, GpuMat(), keypoints_, descriptors_, true);
surf_.downloadKeypoints(keypoints_, features.keypoints);
descriptors_.download(features.descriptors);
}
void SurfFeaturesFinderGpu::collectGarbage()
{
surf_.releaseMemory();
image_.release();
gray_image_.release();
keypoints_.release();
descriptors_.release();
}
#endif
//////////////////////////////////////////////////////////////////////////////
MatchesInfo::MatchesInfo() : src_img_idx(-1), dst_img_idx(-1), num_inliers(0), confidence(0) {}
MatchesInfo::MatchesInfo(const MatchesInfo &other) { *this = other; }
const MatchesInfo& MatchesInfo::operator =(const MatchesInfo &other)
{
src_img_idx = other.src_img_idx;
dst_img_idx = other.dst_img_idx;
matches = other.matches;
inliers_mask = other.inliers_mask;
num_inliers = other.num_inliers;
H = other.H.clone();
confidence = other.confidence;
return *this;
}
//////////////////////////////////////////////////////////////////////////////
void FeaturesMatcher::operator ()(const vector<ImageFeatures> &features, vector<MatchesInfo> &pairwise_matches,
const Mat &mask)
{
const int num_images = static_cast<int>(features.size());
CV_Assert(mask.empty() || (mask.type() == CV_8U && mask.cols == num_images && mask.rows));
Mat_<uchar> mask_(mask);
if (mask_.empty())
mask_ = Mat::ones(num_images, num_images, CV_8U);
vector<pair<int,int> > near_pairs;
for (int i = 0; i < num_images - 1; ++i)
for (int j = i + 1; j < num_images; ++j)
if (features[i].keypoints.size() > 0 && features[j].keypoints.size() > 0 && mask_(i, j))
near_pairs.push_back(make_pair(i, j));
pairwise_matches.resize(num_images * num_images);
MatchPairsBody body(*this, features, pairwise_matches, near_pairs);
if (is_thread_safe_)
parallel_for(BlockedRange(0, static_cast<int>(near_pairs.size())), body);
else
body(BlockedRange(0, static_cast<int>(near_pairs.size())));
LOGLN_CHAT("");
}
//////////////////////////////////////////////////////////////////////////////
BestOf2NearestMatcher::BestOf2NearestMatcher(bool try_use_gpu, float match_conf, int num_matches_thresh1, int num_matches_thresh2)
{
#ifndef ANDROID
if (try_use_gpu && getCudaEnabledDeviceCount() > 0)
impl_ = new GpuMatcher(match_conf);
else
#endif
impl_ = new CpuMatcher(match_conf);
is_thread_safe_ = impl_->isThreadSafe();
num_matches_thresh1_ = num_matches_thresh1;
num_matches_thresh2_ = num_matches_thresh2;
}
void BestOf2NearestMatcher::match(const ImageFeatures &features1, const ImageFeatures &features2,
MatchesInfo &matches_info)
{
(*impl_)(features1, features2, matches_info);
// Check if it makes sense to find homography
if (matches_info.matches.size() < static_cast<size_t>(num_matches_thresh1_))
return;
// Construct point-point correspondences for homography estimation
Mat src_points(1, static_cast<int>(matches_info.matches.size()), CV_32FC2);
Mat dst_points(1, static_cast<int>(matches_info.matches.size()), CV_32FC2);
for (size_t i = 0; i < matches_info.matches.size(); ++i)
{
const DMatch& m = matches_info.matches[i];
Point2f p = features1.keypoints[m.queryIdx].pt;
p.x -= features1.img_size.width * 0.5f;
p.y -= features1.img_size.height * 0.5f;
src_points.at<Point2f>(0, static_cast<int>(i)) = p;
p = features2.keypoints[m.trainIdx].pt;
p.x -= features2.img_size.width * 0.5f;
p.y -= features2.img_size.height * 0.5f;
dst_points.at<Point2f>(0, static_cast<int>(i)) = p;
}
// Find pair-wise motion
matches_info.H = findHomography(src_points, dst_points, matches_info.inliers_mask, CV_RANSAC);
if (std::abs(determinant(matches_info.H)) < numeric_limits<double>::epsilon())
return;
// Find number of inliers
matches_info.num_inliers = 0;
for (size_t i = 0; i < matches_info.inliers_mask.size(); ++i)
if (matches_info.inliers_mask[i])
matches_info.num_inliers++;
// These coeffs are from paper M. Brown and D. Lowe. "Automatic Panoramic Image Stitching
// using Invariant Features"
matches_info.confidence = matches_info.num_inliers / (8 + 0.3 * matches_info.matches.size());
// Set zero confidence to remove matches between too close images, as they don't provide
// additional information anyway. The threshold was set experimentally.
matches_info.confidence = matches_info.confidence > 3. ? 0. : matches_info.confidence;
// Check if we should try to refine motion
if (matches_info.num_inliers < num_matches_thresh2_)
return;
// Construct point-point correspondences for inliers only
src_points.create(1, matches_info.num_inliers, CV_32FC2);
dst_points.create(1, matches_info.num_inliers, CV_32FC2);
int inlier_idx = 0;
for (size_t i = 0; i < matches_info.matches.size(); ++i)
{
if (!matches_info.inliers_mask[i])
continue;
const DMatch& m = matches_info.matches[i];
Point2f p = features1.keypoints[m.queryIdx].pt;
p.x -= features1.img_size.width * 0.5f;
p.y -= features1.img_size.height * 0.5f;
src_points.at<Point2f>(0, inlier_idx) = p;
p = features2.keypoints[m.trainIdx].pt;
p.x -= features2.img_size.width * 0.5f;
p.y -= features2.img_size.height * 0.5f;
dst_points.at<Point2f>(0, inlier_idx) = p;
inlier_idx++;
}
// Rerun motion estimation on inliers only
matches_info.H = findHomography(src_points, dst_points, CV_RANSAC);
}
void BestOf2NearestMatcher::collectGarbage()
{
impl_->collectGarbage();
}
} // namespace detail
} // namespace cv