- updated README

- replaced some printed characters

README.md

@@ -249,6 +249,7 @@ Suggested material:
 * *[Vision Algorithms for Mobile Robotics](http://rpg.ifi.uzh.ch/teaching.html)* by Davide Scaramuzza 
 * *[CS 682 Computer Vision](http://cs.gmu.edu/~kosecka/cs682.html)* by Jana Kosecka   
 * *[The Role of Wide Baseline Stereo in the Deep Learning World](https://ducha-aiki.github.io/wide-baseline-stereo-blog/2020/03/27/intro.html)* by Dmytro Mishkin
+* *[To Learn or Not to Learn: Visual Localization from Essential Matrices](https://arxiv.org/abs/1908.01293)* by Qunjie Zhou, Torsten Sattler, Marc Pollefeys, Laura Leal-Taixe
 * *[Awesome local-global descriptors](https://github.com/shamangary/awesome-local-global-descriptor)* repository 
 
 Moreover, you may want to have a look at the OpenCV [guide](https://docs.opencv.org/3.0-beta/modules/calib3d/doc/camera_calibration_and_3d_reconstruction.html) or [tutorials](https://opencv-python-tutroals.readthedocs.io/en/latest/py_tutorials/py_tutorials.html).  

initializer.py

@@ -129,7 +129,7 @@ def initialize(self, f_cur, img_cur):
         # find keypoint matches
         idxs_cur, idxs_ref = match_frames(f_cur, f_ref, kFeatureMatchRatioTestInitializer)       
 
-        print('├────────')        
+        print('|------------')        
         #print('deque ids: ', [f.id for f in self.frames])
         print('initializing frames ', f_cur.id, ', ', f_ref.id)
         print("# keypoint matches: ", len(idxs_cur))  
@@ -195,5 +195,5 @@ def initialize(self, f_cur, img_cur):
         else:
             self.num_failures += 1            
             Printer.red('Inializer: ko!')                         
-        print('├────────')              
+        print('|------------')               
         return out, is_ok

local_mapping.py

@@ -256,7 +256,7 @@ def process_new_keyframe(self):
 
 
     def cull_map_points(self):
-        print('»» culling map points...')  
+        print('>>>> culling map points...')  
         th_num_observations = 2      
         min_found_ratio = 0.25  
         current_kid = self.kf_cur.kid 
@@ -278,7 +278,7 @@ def cull_map_points(self):
 
 
     def cull_keyframes(self): 
-        print('»» culling keyframes...')    
+        print('>>>> culling keyframes...')    
         num_culled_keyframes = 0
         # check redundant keyframes in local keyframes: a keyframe is considered redundant if the 90% of the MapPoints it sees, 
         # are seen in at least other 3 keyframes (in the same or finer scale)
@@ -339,7 +339,7 @@ def thread_match_function(kf_pair):
 
     # triangulate matched keypoints (without a corresponding map point) amongst recent keyframes      
     def create_new_map_points(self):
-        print('»» creating new map points')
+        print('>>>> creating new map points')
         total_new_pts = 0
 
         local_keyframes = self.map.local_map.get_best_neighbors(self.kf_cur)
@@ -378,7 +378,7 @@ def create_new_map_points(self):
 
     # fuse close map points of local keyframes 
     def fuse_map_points(self):
-        print('»» fusing map points')
+        print('>>>> fusing map points')
         total_fused_pts = 0
 
         local_keyframes = self.map.local_map.get_best_neighbors(self.kf_cur)
@@ -411,4 +411,4 @@ def fuse_map_points(self):
         # update connections in covisibility graph 
         self.kf_cur.update_connections()            
 
-        return total_fused_pts               
+        return total_fused_pts               

slam.py

@@ -264,7 +264,7 @@ def pose_optimization(self, f_cur, name=''):
 
     # track camera motion of f_cur w.r.t. f_ref 
     def track_previous_frame(self, f_ref, f_cur):            
-        print('»» tracking previous frame ...')        
+        print('>>>> tracking previous frame ...')        
         is_search_frame_by_projection_failure = False 
         use_search_frame_by_projection = self.motion_model.is_ok and kUseSearchFrameByProjection and kUseMotionModel
 
@@ -332,7 +332,7 @@ def track_previous_frame(self, f_ref, f_cur):
     # track camera motion of f_cur w.r.t. f_ref
     # estimate motion by matching keypoint descriptors                    
     def track_reference_frame(self, f_ref, f_cur, name=''):
-        print('»» tracking reference %d ...' %(f_ref.id))        
+        print('>>>> tracking reference %d ...' %(f_ref.id))        
         if f_ref is None:
             return 
         # find keypoint matches between f_cur and kf_ref   
@@ -397,7 +397,7 @@ def update_local_map(self):
     def track_local_map(self, f_cur): 
         if self.map.local_map.is_empty():
             return 
-        print('»» tracking local map...')
+        print('>>>> tracking local map...')
         self.timer_seach_map.start()
 
         self.update_local_map()        
@@ -685,11 +685,11 @@ def wait_for_local_mapping(self):
         if kTrackingWaitForLocalMappingToGetIdle:                        
             #while not self.local_mapping.is_idle() or self.local_mapping.queue_size()>0:       
             if not self.local_mapping.is_idle():       
-                print('»» waiting for local mapping...')                         
+                print('>>>> waiting for local mapping...')                         
                 self.local_mapping.wait_idle()
         else:
             if not self.local_mapping.is_idle() and kTrackingWaitForLocalMappingSleepTime>0:
-                print('»» sleeping for local mapping...')                    
+                print('>>>> sleeping for local mapping...')                    
                 time.sleep(kTrackingWaitForLocalMappingSleepTime)  
         # check again for debug                     
         #is_local_mapping_idle = self.local_mapping.is_idle()