Add option num_common_words_thr_ratio (#536)

src/stella_vslam/data/bow_database.cc

@@ -56,6 +56,7 @@ void bow_database::clear() {
 }
 
 std::vector<std::shared_ptr<keyframe>> bow_database::acquire_keyframes(const bow_vector& bow_vec, const float min_score,
+                                                                       const float num_common_words_thr_ratio,
                                                                        const std::set<std::shared_ptr<keyframe>>& keyfrms_to_reject) {
     // Step 1.
     // Count up the number of nodes, words which are shared with query_keyframe, for all the keyframes in DoW database
@@ -74,7 +75,7 @@ std::vector<std::shared_ptr<keyframe>> bow_database::acquire_keyframes(const bow
             max_num_common_words = keyfrm_num_common_words_pair.second;
         }
     }
-    const auto min_num_common_words_thr = static_cast<unsigned int>(0.8f * max_num_common_words);
+    const auto min_num_common_words_thr = static_cast<unsigned int>(num_common_words_thr_ratio * max_num_common_words);
 
     // Step 2.
     // Collect keyframe candidates which have more shared words than min_num_common_words_thr

src/stella_vslam/data/bow_database.h

@@ -51,6 +51,7 @@ class bow_database {
      * Acquire keyframes over score
      */
     std::vector<std::shared_ptr<keyframe>> acquire_keyframes(const bow_vector& bow_vec, const float min_score = 0.0f,
+                                                             const float num_common_words_thr_ratio = 0.8f,
                                                              const std::set<std::shared_ptr<keyframe>>& keyfrms_to_reject = {});
 
 protected:

src/stella_vslam/module/loop_detector.cc

@@ -28,7 +28,8 @@ loop_detector::loop_detector(data::bow_database* bow_db, data::bow_vocabulary* b
       num_matches_thr_brute_force_(yaml_node["num_matches_thr_robust_matcher"].as<unsigned int>(0)),
       num_optimized_inliers_thr_(yaml_node["num_optimized_inliers_thr"].as<unsigned int>(20)),
       top_n_covisibilities_to_search_(yaml_node["top_n_covisibilities_to_search"].as<unsigned int>(0)),
-      use_fixed_seed_(yaml_node["use_fixed_seed"].as<bool>(false)) {
+      use_fixed_seed_(yaml_node["use_fixed_seed"].as<bool>(false)),
+      num_common_words_thr_ratio_(yaml_node["num_common_words_thr_ratio"].as<float>(0.8f)) {
     spdlog::debug("CONSTRUCT: loop_detector");
 }
 
@@ -116,7 +117,7 @@ bool loop_detector::detect_loop_candidates_impl() {
         }
     }
 
-    const auto init_loop_candidates = bow_db_->acquire_keyframes(cur_keyfrm_->bow_vec_, min_score, keyfrms_to_reject);
+    const auto init_loop_candidates = bow_db_->acquire_keyframes(cur_keyfrm_->bow_vec_, min_score, num_common_words_thr_ratio_, keyfrms_to_reject);
 
     // 1-3. if no candidates are found, cannot perform the loop correction
 

src/stella_vslam/module/loop_detector.h

@@ -192,6 +192,8 @@ class loop_detector {
 
     //! Use fixed random seed for RANSAC if true
     const bool use_fixed_seed_;
+
+    const float num_common_words_thr_ratio_ = 0.8f;
 };
 
 } // namespace module

src/stella_vslam/module/relocalizer.cc

@@ -18,13 +18,15 @@ relocalizer::relocalizer(const std::shared_ptr<optimize::pose_optimizer>& pose_o
                          const unsigned int min_num_bow_matches, const unsigned int min_num_valid_obs,
                          const bool use_fixed_seed,
                          const bool search_neighbor,
-                         const unsigned int top_n_covisibilities_to_search)
+                         const unsigned int top_n_covisibilities_to_search,
+                         const float num_common_words_thr_ratio)
     : min_num_bow_matches_(min_num_bow_matches), min_num_valid_obs_(min_num_valid_obs),
       bow_matcher_(bow_match_lowe_ratio, false), proj_matcher_(proj_match_lowe_ratio, false),
       robust_matcher_(robust_match_lowe_ratio, false),
       pose_optimizer_(pose_optimizer), use_fixed_seed_(use_fixed_seed),
       search_neighbor_(search_neighbor),
-      top_n_covisibilities_to_search_(top_n_covisibilities_to_search) {
+      top_n_covisibilities_to_search_(top_n_covisibilities_to_search),
+      num_common_words_thr_ratio_(num_common_words_thr_ratio) {
     spdlog::debug("CONSTRUCT: module::relocalizer");
 }
 
@@ -37,7 +39,8 @@ relocalizer::relocalizer(const std::shared_ptr<optimize::pose_optimizer>& pose_o
                   yaml_node["min_num_valid_obs"].as<unsigned int>(50),
                   yaml_node["use_fixed_seed"].as<bool>(false),
                   yaml_node["search_neighbor"].as<bool>(true),
-                  yaml_node["top_n_covisibilities_to_search"].as<unsigned int>(10)) {
+                  yaml_node["top_n_covisibilities_to_search"].as<unsigned int>(10),
+                  yaml_node["num_common_words_thr_ratio"].as<float>(0.8f)) {
 }
 
 relocalizer::~relocalizer() {
@@ -46,7 +49,7 @@ relocalizer::~relocalizer() {
 
 bool relocalizer::relocalize(data::bow_database* bow_db, data::frame& curr_frm) {
     // Acquire relocalization candidates
-    const auto reloc_candidates = bow_db->acquire_keyframes(curr_frm.bow_vec_);
+    const auto reloc_candidates = bow_db->acquire_keyframes(curr_frm.bow_vec_, 0.0f, num_common_words_thr_ratio_);
     if (reloc_candidates.empty()) {
         return false;
     }

src/stella_vslam/module/relocalizer.h

@@ -27,7 +27,8 @@ class relocalizer {
                          const unsigned int min_num_bow_matches = 20, const unsigned int min_num_valid_obs = 50,
                          const bool use_fixed_seed = false,
                          const bool search_neighbor = true,
-                         const unsigned int top_n_covisibilities_to_search = 10);
+                         const unsigned int top_n_covisibilities_to_search = 10,
+                         const float num_common_words_thr_ratio = 0.8f);
 
     explicit relocalizer(const std::shared_ptr<optimize::pose_optimizer>& pose_optimizer, const YAML::Node& yaml_node);
 
@@ -90,6 +91,8 @@ class relocalizer {
     const bool search_neighbor_ = true;
     //! number of neighbor keyframes
     const unsigned int top_n_covisibilities_to_search_ = 10;
+
+    const float num_common_words_thr_ratio_ = 0.8f;
 };
 
 } // namespace module