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#!/usr/bin/env python3 | |
# Copyright 2004-present Facebook. All Rights Reserved. | |
import numpy as np | |
from typing import List | |
from detectron2.config import CfgNode as CfgNode_ | |
from detectron2.config import configurable | |
from .base_tracker import TRACKER_HEADS_REGISTRY | |
from .vanilla_hungarian_bbox_iou_tracker import VanillaHungarianBBoxIOUTracker | |
class IOUWeightedHungarianBBoxIOUTracker(VanillaHungarianBBoxIOUTracker): | |
""" | |
A tracker using IoU as weight in Hungarian algorithm, also known | |
as Munkres or Kuhn-Munkres algorithm | |
""" | |
def __init__( | |
self, | |
*, | |
video_height: int, | |
video_width: int, | |
max_num_instances: int = 200, | |
max_lost_frame_count: int = 0, | |
min_box_rel_dim: float = 0.02, | |
min_instance_period: int = 1, | |
track_iou_threshold: float = 0.5, | |
**kwargs, | |
): | |
""" | |
Args: | |
video_height: height the video frame | |
video_width: width of the video frame | |
max_num_instances: maximum number of id allowed to be tracked | |
max_lost_frame_count: maximum number of frame an id can lost tracking | |
exceed this number, an id is considered as lost | |
forever | |
min_box_rel_dim: a percentage, smaller than this dimension, a bbox is | |
removed from tracking | |
min_instance_period: an instance will be shown after this number of period | |
since its first showing up in the video | |
track_iou_threshold: iou threshold, below this number a bbox pair is removed | |
from tracking | |
""" | |
super().__init__( | |
video_height=video_height, | |
video_width=video_width, | |
max_num_instances=max_num_instances, | |
max_lost_frame_count=max_lost_frame_count, | |
min_box_rel_dim=min_box_rel_dim, | |
min_instance_period=min_instance_period, | |
track_iou_threshold=track_iou_threshold, | |
) | |
def from_config(cls, cfg: CfgNode_): | |
""" | |
Old style initialization using CfgNode | |
Args: | |
cfg: D2 CfgNode, config file | |
Return: | |
dictionary storing arguments for __init__ method | |
""" | |
assert "VIDEO_HEIGHT" in cfg.TRACKER_HEADS | |
assert "VIDEO_WIDTH" in cfg.TRACKER_HEADS | |
video_height = cfg.TRACKER_HEADS.get("VIDEO_HEIGHT") | |
video_width = cfg.TRACKER_HEADS.get("VIDEO_WIDTH") | |
max_num_instances = cfg.TRACKER_HEADS.get("MAX_NUM_INSTANCES", 200) | |
max_lost_frame_count = cfg.TRACKER_HEADS.get("MAX_LOST_FRAME_COUNT", 0) | |
min_box_rel_dim = cfg.TRACKER_HEADS.get("MIN_BOX_REL_DIM", 0.02) | |
min_instance_period = cfg.TRACKER_HEADS.get("MIN_INSTANCE_PERIOD", 1) | |
track_iou_threshold = cfg.TRACKER_HEADS.get("TRACK_IOU_THRESHOLD", 0.5) | |
return { | |
"_target_": "detectron2.tracking.iou_weighted_hungarian_bbox_iou_tracker.IOUWeightedHungarianBBoxIOUTracker", # noqa | |
"video_height": video_height, | |
"video_width": video_width, | |
"max_num_instances": max_num_instances, | |
"max_lost_frame_count": max_lost_frame_count, | |
"min_box_rel_dim": min_box_rel_dim, | |
"min_instance_period": min_instance_period, | |
"track_iou_threshold": track_iou_threshold, | |
} | |
def assign_cost_matrix_values(self, cost_matrix: np.ndarray, bbox_pairs: List) -> np.ndarray: | |
""" | |
Based on IoU for each pair of bbox, assign the associated value in cost matrix | |
Args: | |
cost_matrix: np.ndarray, initialized 2D array with target dimensions | |
bbox_pairs: list of bbox pair, in each pair, iou value is stored | |
Return: | |
np.ndarray, cost_matrix with assigned values | |
""" | |
for pair in bbox_pairs: | |
# assign (-1 * IoU) for above threshold pairs, algorithms will minimize cost | |
cost_matrix[pair["idx"]][pair["prev_idx"]] = -1 * pair["IoU"] | |
return cost_matrix | |