Fix reid_hit_counter initialization.

norfair/tracker.py

@@ -537,12 +537,12 @@ def __init__(
             self.update_coordinate_transformation(coord_transformations)
 
     def tracker_step(self):
-        self.hit_counter -= 1
         if self.reid_hit_counter is None:
             if self.hit_counter <= 0:
                 self.reid_hit_counter = self.reid_hit_counter_max
         else:
             self.reid_hit_counter -= 1
+        self.hit_counter -= 1
         self.point_hit_counter -= 1
         self.age += 1
         # Advances the tracker's state

tests/test_tracker.py

@@ -299,6 +299,60 @@ def test_multiple_trackers():
     assert tracker2.total_object_count == 1
 
 
+def test_reid_hit_counter():
+    #
+    # test reid hit counter and initializations
+    #
+
+    # simple reid distance
+    def dist(new_obj, tracked_obj):
+        return np.linalg.norm(new_obj.estimate - tracked_obj.estimate)
+
+    hit_counter_max = 2
+    reid_hit_counter_max = 2
+
+    tracker = Tracker(
+        distance_function="euclidean",
+        distance_threshold=1,
+        hit_counter_max=hit_counter_max,
+        initialization_delay=1,
+        reid_distance_function=dist,
+        reid_distance_threshold=5,
+        reid_hit_counter_max=reid_hit_counter_max,
+    )
+
+    tracked_objects = tracker.update([Detection(points=np.array([[1, 1]]))])
+    tracked_objects = tracker.update([Detection(points=np.array([[1, 1]]))])
+
+    # check that hit counters initialize correctly
+    assert len(tracked_objects) == 1
+    assert tracked_objects[0].hit_counter == 2
+    assert tracked_objects[0].reid_hit_counter == None
+
+    # check that object is dead if it doesn't get matched to any detections
+    obj_id = tracked_objects[0].id
+    for _ in range(hit_counter_max + 1):
+        tracked_objects = tracker.update()
+    assert len(tracked_objects) == 0
+
+    # check that previous object gets back to life after reid matching
+    for _ in range(hit_counter_max):
+        tracked_objects = tracker.update([Detection(points=np.array([[2, 2]]))])
+    assert len(tracked_objects) == 1
+    assert tracked_objects[0].id == obj_id
+    assert tracked_objects[0].reid_hit_counter == None
+    assert tracked_objects[0].hit_counter == hit_counter_max
+
+    # check that previous object gets eliminated after hit_counter_max + reid_hit_counter_max + 1
+    for _ in range(hit_counter_max + reid_hit_counter_max + 1):
+        tracked_objects = tracker.update()
+    assert len(tracked_objects) == 0
+    for _ in range(2):
+        tracked_objects = tracker.update([Detection(points=np.array([[1, 1]]))])
+    assert len(tracked_objects) == 1
+    assert tracked_objects[0].id != obj_id
+
+
 # TODO tests list:
 #   - detections with different labels
 #   - partial matches where some points are missing