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			242 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			242 lines
		
	
	
		
			9.3 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
import random
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import string
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from collections import defaultdict
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import numpy as np
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from scipy.spatial import distance as dist
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from frigate.config import DetectConfig
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from frigate.track import ObjectTracker
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from frigate.util import intersection_over_union
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class CentroidTracker(ObjectTracker):
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    def __init__(self, config: DetectConfig):
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        self.tracked_objects = {}
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        self.untracked_object_boxes = []
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        self.disappeared = {}
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        self.positions = {}
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        self.max_disappeared = config.max_disappeared
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        self.detect_config = config
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    def register(self, index, obj):
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        rand_id = "".join(random.choices(string.ascii_lowercase + string.digits, k=6))
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        id = f"{obj['frame_time']}-{rand_id}"
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        obj["id"] = id
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        obj["start_time"] = obj["frame_time"]
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        obj["motionless_count"] = 0
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        obj["position_changes"] = 0
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        self.tracked_objects[id] = obj
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        self.disappeared[id] = 0
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        self.positions[id] = {
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            "xmins": [],
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            "ymins": [],
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            "xmaxs": [],
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            "ymaxs": [],
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            "xmin": 0,
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            "ymin": 0,
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            "xmax": self.detect_config.width,
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            "ymax": self.detect_config.height,
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        }
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    def deregister(self, id):
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        del self.tracked_objects[id]
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        del self.disappeared[id]
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    # tracks the current position of the object based on the last N bounding boxes
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    # returns False if the object has moved outside its previous position
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    def update_position(self, id, box):
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        position = self.positions[id]
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        position_box = (
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            position["xmin"],
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            position["ymin"],
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            position["xmax"],
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            position["ymax"],
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        )
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        xmin, ymin, xmax, ymax = box
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        iou = intersection_over_union(position_box, box)
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        # if the iou drops below the threshold
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        # assume the object has moved to a new position and reset the computed box
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        if iou < 0.6:
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            self.positions[id] = {
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                "xmins": [xmin],
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                "ymins": [ymin],
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                "xmaxs": [xmax],
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                "ymaxs": [ymax],
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                "xmin": xmin,
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                "ymin": ymin,
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                "xmax": xmax,
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                "ymax": ymax,
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            }
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            return False
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        # if there are less than 10 entries for the position, add the bounding box
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        # and recompute the position box
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        if len(position["xmins"]) < 10:
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            position["xmins"].append(xmin)
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            position["ymins"].append(ymin)
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            position["xmaxs"].append(xmax)
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            position["ymaxs"].append(ymax)
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            # by using percentiles here, we hopefully remove outliers
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            position["xmin"] = np.percentile(position["xmins"], 15)
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            position["ymin"] = np.percentile(position["ymins"], 15)
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            position["xmax"] = np.percentile(position["xmaxs"], 85)
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            position["ymax"] = np.percentile(position["ymaxs"], 85)
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        return True
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    def is_expired(self, id):
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        obj = self.tracked_objects[id]
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        # get the max frames for this label type or the default
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        max_frames = self.detect_config.stationary.max_frames.objects.get(
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            obj["label"], self.detect_config.stationary.max_frames.default
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        )
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        # if there is no max_frames for this label type, continue
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        if max_frames is None:
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            return False
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        # if the object has exceeded the max_frames setting, deregister
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        if (
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            obj["motionless_count"] - self.detect_config.stationary.threshold
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            > max_frames
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        ):
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            return True
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        return False
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    def update(self, id, new_obj):
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        self.disappeared[id] = 0
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        # update the motionless count if the object has not moved to a new position
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        if self.update_position(id, new_obj["box"]):
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            self.tracked_objects[id]["motionless_count"] += 1
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            if self.is_expired(id):
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                self.deregister(id)
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                return
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        else:
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            # register the first position change and then only increment if
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            # the object was previously stationary
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            if (
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                self.tracked_objects[id]["position_changes"] == 0
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                or self.tracked_objects[id]["motionless_count"]
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                >= self.detect_config.stationary.threshold
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            ):
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                self.tracked_objects[id]["position_changes"] += 1
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            self.tracked_objects[id]["motionless_count"] = 0
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        self.tracked_objects[id].update(new_obj)
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    def update_frame_times(self, frame_name, frame_time):
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        for id in list(self.tracked_objects.keys()):
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            self.tracked_objects[id]["frame_time"] = frame_time
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            self.tracked_objects[id]["motionless_count"] += 1
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            if self.is_expired(id):
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                self.deregister(id)
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    def match_and_update(self, frame_time, detections):
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        # group by name
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        detection_groups = defaultdict(lambda: [])
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        for obj in detections:
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            detection_groups[obj[0]].append(
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                {
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                    "label": obj[0],
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                    "score": obj[1],
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                    "box": obj[2],
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                    "area": obj[3],
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                    "ratio": obj[4],
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                    "region": obj[5],
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                    "frame_time": frame_time,
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                }
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            )
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        # update any tracked objects with labels that are not
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        # seen in the current objects and deregister if needed
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        for obj in list(self.tracked_objects.values()):
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            if obj["label"] not in detection_groups:
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                if self.disappeared[obj["id"]] >= self.max_disappeared:
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                    self.deregister(obj["id"])
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                else:
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                    self.disappeared[obj["id"]] += 1
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        if len(detections) == 0:
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            return
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        # track objects for each label type
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        for label, group in detection_groups.items():
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            current_objects = [
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                o for o in self.tracked_objects.values() if o["label"] == label
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            ]
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            current_ids = [o["id"] for o in current_objects]
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            current_centroids = np.array([o["centroid"] for o in current_objects])
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            # compute centroids of new objects
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            for obj in group:
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                centroid_x = int((obj["box"][0] + obj["box"][2]) / 2.0)
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                centroid_y = int((obj["box"][1] + obj["box"][3]) / 2.0)
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                obj["centroid"] = (centroid_x, centroid_y)
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            if len(current_objects) == 0:
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                for index, obj in enumerate(group):
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                    self.register(index, obj)
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                continue
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            new_centroids = np.array([o["centroid"] for o in group])
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            # compute the distance between each pair of tracked
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            # centroids and new centroids, respectively -- our
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            # goal will be to match each current centroid to a new
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            # object centroid
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            D = dist.cdist(current_centroids, new_centroids)
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            # in order to perform this matching we must (1) find the smallest
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            # value in each row (i.e. the distance from each current object to
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            # the closest new object) and then (2) sort the row indexes based
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            # on their minimum values so that the row with the smallest
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            # distance (the best match) is at the *front* of the index list
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            rows = D.min(axis=1).argsort()
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            # next, we determine which new object each existing object matched
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            # against, and apply the same sorting as was applied previously
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            cols = D.argmin(axis=1)[rows]
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            # many current objects may register with each new object, so only
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            # match the closest ones.  unique returns the indices of the first
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            # occurrences of each value, and because the rows are sorted by
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            # distance, this will be index of the closest match
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            _, index = np.unique(cols, return_index=True)
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            rows = rows[index]
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            cols = cols[index]
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            # loop over the combination of the (row, column) index tuples
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            for row, col in zip(rows, cols):
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                # grab the object ID for the current row, set its new centroid,
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                # and reset the disappeared counter
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                objectID = current_ids[row]
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                self.update(objectID, group[col])
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            # compute the row and column indices we have NOT yet examined
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            unusedRows = set(range(D.shape[0])).difference(rows)
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            unusedCols = set(range(D.shape[1])).difference(cols)
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            # in the event that the number of object centroids is
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            # equal or greater than the number of input centroids
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            # we need to check and see if some of these objects have
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            # potentially disappeared
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            if D.shape[0] >= D.shape[1]:
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                for row in unusedRows:
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                    id = current_ids[row]
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                    if self.disappeared[id] >= self.max_disappeared:
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                        self.deregister(id)
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                    else:
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                        self.disappeared[id] += 1
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            # if the number of input centroids is greater
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            # than the number of existing object centroids we need to
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            # register each new input centroid as a trackable object
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            else:
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                for col in unusedCols:
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                    self.register(col, group[col])
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