asso func created initalized on first frame

boxmot/trackers/basetracker.py

@@ -4,6 +4,7 @@
 import colorsys
 from abc import ABC, abstractmethod
 from boxmot.utils import logger as LOGGER
+from boxmot.utils.iou import AssociationFunction
 
 
 class BaseTracker(ABC):
@@ -15,7 +16,8 @@ def __init__(
         iou_threshold: float = 0.3,
         max_obs: int = 50,
         nr_classes: int = 80,
-        per_class: bool = False
+        per_class: bool = False,
+        asso_func: str = 'iou'
     ):
         """
         Initialize the BaseTracker object with detection threshold, maximum age, minimum hits, 
@@ -39,10 +41,12 @@ def __init__(
         self.nr_classes = nr_classes
         self.iou_threshold = iou_threshold
         self.last_emb_size = None
+        self.asso_func_name = asso_func
 
         self.frame_count = 0
         self.active_tracks = []  # This might be handled differently in derived classes
         self.per_class_active_tracks = None
+        self._first_frame_processed = False  # Flag to track if the first frame has been processed
 
         # Initialize per-class active tracks
         if self.per_class:
@@ -92,6 +96,29 @@ def get_class_dets_n_embs(self, dets, embs, cls_id):
                     class_embs = None
         return class_dets, class_embs
 
+    @staticmethod
+    def on_first_frame_setup(method):
+        """
+        Decorator to perform setup on the first frame only.
+        This ensures that initialization tasks (like setting the association function) only
+        happen once, on the first frame, and are skipped on subsequent frames.
+        """
+        def wrapper(self, *args, **kwargs):
+            # If setup hasn't been done yet, perform it
+            if not self._first_frame_processed:
+                img = args[1]
+                self.h, self.w = img.shape[0:2]
+                self.asso_func = AssociationFunction(w=self.w, h=self.h, asso_mode=self.asso_func_name).asso_func
+
+                # Mark that the first frame setup has been done
+                self._first_frame_processed = True
+
+            # Call the original method (e.g., update)
+            return method(self, *args, **kwargs)
+
+        return wrapper
+
+
     @staticmethod
     def per_class_decorator(update_method):
         """