opencv/modules/stitching/matchers.cpp

358 lines
12 KiB
C++

#include <algorithm>
#include <functional>
#include <opencv2/calib3d/calib3d.hpp>
#include <opencv2/gpu/gpu.hpp>
#include "matchers.hpp"
#include "util.hpp"
using namespace std;
using namespace cv;
using namespace cv::gpu;
//////////////////////////////////////////////////////////////////////////////
namespace
{
class CpuSurfFeaturesFinder : public FeaturesFinder
{
public:
inline CpuSurfFeaturesFinder(double hess_thresh, int num_octaves, int num_layers,
int num_octaves_descr, int num_layers_descr)
{
detector_ = new SurfFeatureDetector(hess_thresh, num_octaves, num_layers);
extractor_ = new SurfDescriptorExtractor(num_octaves_descr, num_layers_descr);
}
protected:
void find(const vector<Mat> &images, vector<ImageFeatures> &features);
private:
Ptr<FeatureDetector> detector_;
Ptr<DescriptorExtractor> extractor_;
};
void CpuSurfFeaturesFinder::find(const vector<Mat> &images, vector<ImageFeatures> &features)
{
// Make images gray
vector<Mat> gray_images(images.size());
for (size_t i = 0; i < images.size(); ++i)
{
CV_Assert(images[i].depth() == CV_8U);
cvtColor(images[i], gray_images[i], CV_BGR2GRAY);
}
features.resize(images.size());
// Find keypoints in all images
for (size_t i = 0; i < images.size(); ++i)
{
detector_->detect(gray_images[i], features[i].keypoints);
extractor_->compute(gray_images[i], features[i].keypoints, features[i].descriptors);
}
}
class GpuSurfFeaturesFinder : public FeaturesFinder
{
public:
inline GpuSurfFeaturesFinder(double hess_thresh, int num_octaves, int num_layers,
int num_octaves_descr, int num_layers_descr)
{
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;
}
protected:
void find(const vector<Mat> &images, vector<ImageFeatures> &features);
private:
SURF_GPU surf_;
int num_octaves_, num_layers_;
int num_octaves_descr_, num_layers_descr_;
};
void GpuSurfFeaturesFinder::find(const vector<Mat> &images, vector<ImageFeatures> &features)
{
// Make images gray
vector<GpuMat> gray_images(images.size());
for (size_t i = 0; i < images.size(); ++i)
{
CV_Assert(images[i].depth() == CV_8U);
cvtColor(GpuMat(images[i]), gray_images[i], CV_BGR2GRAY);
}
features.resize(images.size());
// Find keypoints in all images
GpuMat d_keypoints;
GpuMat d_descriptors;
for (size_t i = 0; i < images.size(); ++i)
{
surf_.nOctaves = num_octaves_;
surf_.nOctaveLayers = num_layers_;
surf_(gray_images[i], GpuMat(), d_keypoints);
surf_.nOctaves = num_octaves_descr_;
surf_.nOctaveLayers = num_layers_descr_;
surf_(gray_images[i], GpuMat(), d_keypoints, d_descriptors, true);
surf_.downloadKeypoints(d_keypoints, features[i].keypoints);
d_descriptors.download(features[i].descriptors);
}
}
}
SurfFeaturesFinder::SurfFeaturesFinder(bool try_use_gpu, double hess_thresh, int num_octaves, int num_layers,
int num_octaves_descr, int num_layers_descr)
{
if (try_use_gpu && getCudaEnabledDeviceCount() > 0)
impl_ = new GpuSurfFeaturesFinder(hess_thresh, num_octaves, num_layers, num_octaves_descr, num_layers_descr);
else
impl_ = new CpuSurfFeaturesFinder(hess_thresh, num_octaves, num_layers, num_octaves_descr, num_layers_descr);
}
void SurfFeaturesFinder::find(const vector<Mat> &images, vector<ImageFeatures> &features)
{
(*impl_)(images, features);
}
//////////////////////////////////////////////////////////////////////////////
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<Mat> &images, const vector<ImageFeatures> &features,
vector<MatchesInfo> &pairwise_matches)
{
pairwise_matches.resize(images.size() * images.size());
for (size_t i = 0; i < images.size(); ++i)
{
LOGLN("Processing image " << i << "... ");
for (size_t j = 0; j < images.size(); ++j)
{
if (i == j)
continue;
size_t pair_idx = i * images.size() + j;
(*this)(images[i], features[i], images[j], features[j], pairwise_matches[pair_idx]);
pairwise_matches[pair_idx].src_img_idx = i;
pairwise_matches[pair_idx].dst_img_idx = j;
}
}
}
//////////////////////////////////////////////////////////////////////////////
namespace
{
class CpuMatcher : public FeaturesMatcher
{
public:
inline CpuMatcher(float match_conf) : match_conf_(match_conf) {}
void match(const cv::Mat&, const ImageFeatures &features1, const cv::Mat&, const ImageFeatures &features2, MatchesInfo& matches_info);
private:
float match_conf_;
};
void CpuMatcher::match(const cv::Mat&, const ImageFeatures &features1, const cv::Mat&, const ImageFeatures &features2, MatchesInfo& matches_info)
{
matches_info.matches.clear();
BruteForceMatcher< L2<float> > matcher;
vector< vector<DMatch> > pair_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);
}
// 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)
matches_info.matches.push_back(DMatch(m0.trainIdx, m0.queryIdx, m0.distance));
}
}
class GpuMatcher : public FeaturesMatcher
{
public:
inline GpuMatcher(float match_conf) : match_conf_(match_conf) {}
void match(const cv::Mat&, const ImageFeatures &features1, const cv::Mat&, const ImageFeatures &features2, MatchesInfo& matches_info);
private:
float match_conf_;
GpuMat descriptors1_;
GpuMat descriptors2_;
GpuMat trainIdx_, distance_, allDist_;
};
void GpuMatcher::match(const cv::Mat&, const ImageFeatures &features1, const cv::Mat&, const ImageFeatures &features2, MatchesInfo& matches_info)
{
matches_info.matches.clear();
BruteForceMatcher_GPU< L2<float> > matcher;
descriptors1_.upload(features1.descriptors);
descriptors2_.upload(features2.descriptors);
vector< vector<DMatch> > pair_matches;
// Find 1->2 matches
matcher.knnMatch(descriptors1_, descriptors2_, trainIdx_, distance_, allDist_, 2);
matcher.knnMatchDownload(trainIdx_, 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];
CV_Assert(m0.queryIdx < static_cast<int>(features1.keypoints.size()));
CV_Assert(m0.trainIdx < static_cast<int>(features2.keypoints.size()));
if (m0.distance < (1.f - match_conf_) * m1.distance)
matches_info.matches.push_back(m0);
}
// Find 2->1 matches
pair_matches.clear();
matcher.knnMatch(descriptors2_, descriptors1_, trainIdx_, distance_, allDist_, 2);
matcher.knnMatchDownload(trainIdx_, 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];
CV_Assert(m0.trainIdx < static_cast<int>(features1.keypoints.size()));
CV_Assert(m0.queryIdx < static_cast<int>(features2.keypoints.size()));
if (m0.distance < (1.f - match_conf_) * m1.distance)
matches_info.matches.push_back(DMatch(m0.trainIdx, m0.queryIdx, m0.distance));
}
}
}
BestOf2NearestMatcher::BestOf2NearestMatcher(bool try_use_gpu, float match_conf, int num_matches_thresh1, int num_matches_thresh2)
{
if (try_use_gpu && getCudaEnabledDeviceCount() > 0)
impl_ = new GpuMatcher(match_conf);
else
impl_ = new CpuMatcher(match_conf);
num_matches_thresh1_ = num_matches_thresh1;
num_matches_thresh2_ = num_matches_thresh2;
}
void BestOf2NearestMatcher::match(const Mat &img1, const ImageFeatures &features1, const Mat &img2, const ImageFeatures &features2,
MatchesInfo &matches_info)
{
(*impl_)(img1, features1, img2, 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, matches_info.matches.size(), CV_32FC2);
Mat dst_points(1, 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 -= img1.cols * 0.5f;
p.y -= img1.rows * 0.5f;
src_points.at<Point2f>(0, i) = p;
p = features2.keypoints[m.trainIdx].pt;
p.x -= img2.cols * 0.5f;
p.y -= img2.rows * 0.5f;
dst_points.at<Point2f>(0, i) = p;
}
// Find pair-wise motion
matches_info.H = findHomography(src_points, dst_points, matches_info.inliers_mask, CV_RANSAC);
// 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++;
matches_info.confidence = matches_info.num_inliers / (8 + 0.3*matches_info.matches.size());
// 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 -= img1.cols * 0.5f;
p.y -= img2.rows * 0.5f;
src_points.at<Point2f>(0, inlier_idx) = p;
p = features2.keypoints[m.trainIdx].pt;
p.x -= img2.cols * 0.5f;
p.y -= img2.rows * 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);
}