Features Finding and Images Matching ==================================== .. highlight:: cpp detail::ImageFeatures ----------------------- .. ocv:struct:: detail::ImageFeatures Structure containing image keypoints and descriptors. :: struct CV_EXPORTS ImageFeatures { int img_idx; Size img_size; std::vector keypoints; Mat descriptors; }; detail::FeaturesFinder ---------------------- .. ocv:class:: detail::FeaturesFinder Feature finders base class. :: class CV_EXPORTS FeaturesFinder { public: virtual ~FeaturesFinder() {} void operator ()(const Mat &image, ImageFeatures &features); void operator ()(const Mat &image, ImageFeatures &features, const std::vector &rois); virtual void collectGarbage() {} protected: virtual void find(const Mat &image, ImageFeatures &features) = 0; }; detail::FeaturesFinder::operator() ---------------------------------- Finds features in the given image. .. ocv:function:: void detail::FeaturesFinder::operator ()(const Mat &image, ImageFeatures &features) .. ocv:function:: void detail::FeaturesFinder::operator ()(const Mat &image, ImageFeatures &features, const std::vector &rois) :param image: Source image :param features: Found features :param rois: Regions of interest .. seealso:: :ocv:struct:`detail::ImageFeatures`, :ocv:class:`Rect_` detail::FeaturesFinder::collectGarbage -------------------------------------- Frees unused memory allocated before if there is any. .. ocv:function:: void detail::FeaturesFinder::collectGarbage() detail::FeaturesFinder::find ---------------------------- This method must implement features finding logic in order to make the wrappers `detail::FeaturesFinder::operator()`_ work. .. ocv:function:: void detail::FeaturesFinder::find(const Mat &image, ImageFeatures &features) :param image: Source image :param features: Found features .. seealso:: :ocv:struct:`detail::ImageFeatures` detail::SurfFeaturesFinder -------------------------- .. ocv:class:: detail::SurfFeaturesFinder : public detail::FeaturesFinder SURF features finder. :: class CV_EXPORTS SurfFeaturesFinder : public FeaturesFinder { public: SurfFeaturesFinder(double hess_thresh = 300., int num_octaves = 3, int num_layers = 4, int num_octaves_descr = /*4*/3, int num_layers_descr = /*2*/4); private: /* hidden */ }; .. seealso:: :ocv:class:`detail::FeaturesFinder`, :ocv:class:`SURF` detail::OrbFeaturesFinder ------------------------- .. ocv:class:: detail::OrbFeaturesFinder : public detail::FeaturesFinder ORB features finder. :: class CV_EXPORTS OrbFeaturesFinder : public FeaturesFinder { public: OrbFeaturesFinder(Size _grid_size = Size(3,1), size_t n_features = 1500, const ORB::CommonParams &detector_params = ORB::CommonParams(1.3f, 5)); private: /* hidden */ }; .. seealso:: :ocv:class:`detail::FeaturesFinder`, :ocv:class:`ORB` detail::MatchesInfo ------------------- .. ocv:struct:: detail::MatchesInfo Structure containing information about matches between two images. It's assumed that there is a homography between those images. :: struct CV_EXPORTS MatchesInfo { MatchesInfo(); MatchesInfo(const MatchesInfo &other); const MatchesInfo& operator =(const MatchesInfo &other); int src_img_idx, dst_img_idx; // Images indices (optional) std::vector matches; std::vector inliers_mask; // Geometrically consistent matches mask int num_inliers; // Number of geometrically consistent matches Mat H; // Estimated homography double confidence; // Confidence two images are from the same panorama }; detail::FeaturesMatcher ----------------------- .. ocv:class:: detail::FeaturesMatcher Feature matchers base class. :: class CV_EXPORTS FeaturesMatcher { public: virtual ~FeaturesMatcher() {} void operator ()(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info) { match(features1, features2, matches_info); } void operator ()(const std::vector &features, std::vector &pairwise_matches, const Mat &mask = cv::Mat()); bool isThreadSafe() const { return is_thread_safe_; } virtual void collectGarbage() {} protected: FeaturesMatcher(bool is_thread_safe = false) : is_thread_safe_(is_thread_safe) {} virtual void match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info) = 0; bool is_thread_safe_; }; detail::FeaturesMatcher::operator() ----------------------------------- Performs images matching. .. ocv:function:: void detail::FeaturesMatcher::operator ()(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info) :param features1: First image features :param features2: Second image features :param matches_info: Found matches .. ocv:function:: void detail::FeaturesMatcher::operator ()( const std::vector & features, std::vector & pairwise_matches, const Mat & mask=Mat() ) :param features: Features of the source images :param pairwise_matches: Found pairwise matches :param mask: Mask indicating which image pairs must be matched The function is parallelized with the TBB library. .. seealso:: :ocv:struct:`detail::MatchesInfo` detail::FeaturesMatcher::isThreadSafe ------------------------------------- .. ocv:function:: bool detail::FeaturesMatcher::isThreadSafe() const :return: True, if it's possible to use the same matcher instance in parallel, false otherwise detail::FeaturesMatcher::collectGarbage --------------------------------------- Frees unused memory allocated before if there is any. .. ocv:function:: void detail::FeaturesMatcher::collectGarbage() detail::FeaturesMatcher::match ------------------------------ This method must implement matching logic in order to make the wrappers `detail::FeaturesMatcher::operator()`_ work. .. ocv:function:: void detail::FeaturesMatcher::match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo& matches_info) :param features1: first image features :param features2: second image features :param matches_info: found matches detail::BestOf2NearestMatcher ----------------------------- .. ocv:class:: detail::BestOf2NearestMatcher : public detail::FeaturesMatcher Features matcher which finds two best matches for each feature and leaves the best one only if the ratio between descriptor distances is greater than the threshold ``match_conf``. :: class CV_EXPORTS BestOf2NearestMatcher : public FeaturesMatcher { public: BestOf2NearestMatcher(bool try_use_gpu = false, float match_conf = 0.65f, int num_matches_thresh1 = 6, int num_matches_thresh2 = 6); void collectGarbage(); protected: void match(const ImageFeatures &features1, const ImageFeatures &features2, MatchesInfo &matches_info); int num_matches_thresh1_; int num_matches_thresh2_; Ptr impl_; }; .. seealso:: :ocv:class:`detail::FeaturesMatcher` detail::BestOf2NearestMatcher::BestOf2NearestMatcher ---------------------------------------------------- Constructs a "best of 2 nearest" matcher. .. ocv:function:: detail::BestOf2NearestMatcher::BestOf2NearestMatcher(bool try_use_gpu = false, float match_conf = 0.3f, int num_matches_thresh1 = 6, int num_matches_thresh2 = 6) :param try_use_gpu: Should try to use GPU or not :param match_conf: Match distances ration threshold :param num_matches_thresh1: Minimum number of matches required for the 2D projective transform estimation used in the inliers classification step :param num_matches_thresh2: Minimum number of matches required for the 2D projective transform re-estimation on inliers