File size: 30,551 Bytes
18dd6ad
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
# Copyright (c) Facebook, Inc. and its affiliates.
import contextlib
import copy
import io
import itertools
import json
import logging
import numpy as np
import os
import pickle
from collections import OrderedDict
import pycocotools.mask as mask_util
import torch
from pycocotools.coco import COCO
from pycocotools.cocoeval import COCOeval
from tabulate import tabulate

import annotator.oneformer.detectron2.utils.comm as comm
from annotator.oneformer.detectron2.config import CfgNode
from annotator.oneformer.detectron2.data import MetadataCatalog
from annotator.oneformer.detectron2.data.datasets.coco import convert_to_coco_json
from annotator.oneformer.detectron2.structures import Boxes, BoxMode, pairwise_iou
from annotator.oneformer.detectron2.utils.file_io import PathManager
from annotator.oneformer.detectron2.utils.logger import create_small_table

from .evaluator import DatasetEvaluator

try:
    from annotator.oneformer.detectron2.evaluation.fast_eval_api import COCOeval_opt
except ImportError:
    COCOeval_opt = COCOeval


class COCOEvaluator(DatasetEvaluator):
    """
    Evaluate AR for object proposals, AP for instance detection/segmentation, AP
    for keypoint detection outputs using COCO's metrics.
    See http://cocodataset.org/#detection-eval and
    http://cocodataset.org/#keypoints-eval to understand its metrics.
    The metrics range from 0 to 100 (instead of 0 to 1), where a -1 or NaN means
    the metric cannot be computed (e.g. due to no predictions made).

    In addition to COCO, this evaluator is able to support any bounding box detection,
    instance segmentation, or keypoint detection dataset.
    """

    def __init__(
        self,
        dataset_name,
        tasks=None,
        distributed=True,
        output_dir=None,
        *,
        max_dets_per_image=None,
        use_fast_impl=True,
        kpt_oks_sigmas=(),
        allow_cached_coco=True,
    ):
        """
        Args:
            dataset_name (str): name of the dataset to be evaluated.
                It must have either the following corresponding metadata:

                    "json_file": the path to the COCO format annotation

                Or it must be in detectron2's standard dataset format
                so it can be converted to COCO format automatically.
            tasks (tuple[str]): tasks that can be evaluated under the given
                configuration. A task is one of "bbox", "segm", "keypoints".
                By default, will infer this automatically from predictions.
            distributed (True): if True, will collect results from all ranks and run evaluation
                in the main process.
                Otherwise, will only evaluate the results in the current process.
            output_dir (str): optional, an output directory to dump all
                results predicted on the dataset. The dump contains two files:

                1. "instances_predictions.pth" a file that can be loaded with `torch.load` and
                   contains all the results in the format they are produced by the model.
                2. "coco_instances_results.json" a json file in COCO's result format.
            max_dets_per_image (int): limit on the maximum number of detections per image.
                By default in COCO, this limit is to 100, but this can be customized
                to be greater, as is needed in evaluation metrics AP fixed and AP pool
                (see https://arxiv.org/pdf/2102.01066.pdf)
                This doesn't affect keypoint evaluation.
            use_fast_impl (bool): use a fast but **unofficial** implementation to compute AP.
                Although the results should be very close to the official implementation in COCO
                API, it is still recommended to compute results with the official API for use in
                papers. The faster implementation also uses more RAM.
            kpt_oks_sigmas (list[float]): The sigmas used to calculate keypoint OKS.
                See http://cocodataset.org/#keypoints-eval
                When empty, it will use the defaults in COCO.
                Otherwise it should be the same length as ROI_KEYPOINT_HEAD.NUM_KEYPOINTS.
            allow_cached_coco (bool): Whether to use cached coco json from previous validation
                runs. You should set this to False if you need to use different validation data.
                Defaults to True.
        """
        self._logger = logging.getLogger(__name__)
        self._distributed = distributed
        self._output_dir = output_dir

        if use_fast_impl and (COCOeval_opt is COCOeval):
            self._logger.info("Fast COCO eval is not built. Falling back to official COCO eval.")
            use_fast_impl = False
        self._use_fast_impl = use_fast_impl

        # COCOeval requires the limit on the number of detections per image (maxDets) to be a list
        # with at least 3 elements. The default maxDets in COCOeval is [1, 10, 100], in which the
        # 3rd element (100) is used as the limit on the number of detections per image when
        # evaluating AP. COCOEvaluator expects an integer for max_dets_per_image, so for COCOeval,
        # we reformat max_dets_per_image into [1, 10, max_dets_per_image], based on the defaults.
        if max_dets_per_image is None:
            max_dets_per_image = [1, 10, 100]
        else:
            max_dets_per_image = [1, 10, max_dets_per_image]
        self._max_dets_per_image = max_dets_per_image

        if tasks is not None and isinstance(tasks, CfgNode):
            kpt_oks_sigmas = (
                tasks.TEST.KEYPOINT_OKS_SIGMAS if not kpt_oks_sigmas else kpt_oks_sigmas
            )
            self._logger.warn(
                "COCO Evaluator instantiated using config, this is deprecated behavior."
                " Please pass in explicit arguments instead."
            )
            self._tasks = None  # Infering it from predictions should be better
        else:
            self._tasks = tasks

        self._cpu_device = torch.device("cpu")

        self._metadata = MetadataCatalog.get(dataset_name)
        if not hasattr(self._metadata, "json_file"):
            if output_dir is None:
                raise ValueError(
                    "output_dir must be provided to COCOEvaluator "
                    "for datasets not in COCO format."
                )
            self._logger.info(f"Trying to convert '{dataset_name}' to COCO format ...")

            cache_path = os.path.join(output_dir, f"{dataset_name}_coco_format.json")
            self._metadata.json_file = cache_path
            convert_to_coco_json(dataset_name, cache_path, allow_cached=allow_cached_coco)

        json_file = PathManager.get_local_path(self._metadata.json_file)
        with contextlib.redirect_stdout(io.StringIO()):
            self._coco_api = COCO(json_file)

        # Test set json files do not contain annotations (evaluation must be
        # performed using the COCO evaluation server).
        self._do_evaluation = "annotations" in self._coco_api.dataset
        if self._do_evaluation:
            self._kpt_oks_sigmas = kpt_oks_sigmas

    def reset(self):
        self._predictions = []

    def process(self, inputs, outputs):
        """
        Args:
            inputs: the inputs to a COCO model (e.g., GeneralizedRCNN).
                It is a list of dict. Each dict corresponds to an image and
                contains keys like "height", "width", "file_name", "image_id".
            outputs: the outputs of a COCO model. It is a list of dicts with key
                "instances" that contains :class:`Instances`.
        """
        for input, output in zip(inputs, outputs):
            prediction = {"image_id": input["image_id"]}

            if "instances" in output:
                instances = output["instances"].to(self._cpu_device)
                prediction["instances"] = instances_to_coco_json(instances, input["image_id"])
            if "proposals" in output:
                prediction["proposals"] = output["proposals"].to(self._cpu_device)
            if len(prediction) > 1:
                self._predictions.append(prediction)

    def evaluate(self, img_ids=None):
        """
        Args:
            img_ids: a list of image IDs to evaluate on. Default to None for the whole dataset
        """
        if self._distributed:
            comm.synchronize()
            predictions = comm.gather(self._predictions, dst=0)
            predictions = list(itertools.chain(*predictions))

            if not comm.is_main_process():
                return {}
        else:
            predictions = self._predictions

        if len(predictions) == 0:
            self._logger.warning("[COCOEvaluator] Did not receive valid predictions.")
            return {}

        if self._output_dir:
            PathManager.mkdirs(self._output_dir)
            file_path = os.path.join(self._output_dir, "instances_predictions.pth")
            with PathManager.open(file_path, "wb") as f:
                torch.save(predictions, f)

        self._results = OrderedDict()
        if "proposals" in predictions[0]:
            self._eval_box_proposals(predictions)
        if "instances" in predictions[0]:
            self._eval_predictions(predictions, img_ids=img_ids)
        # Copy so the caller can do whatever with results
        return copy.deepcopy(self._results)

    def _tasks_from_predictions(self, predictions):
        """
        Get COCO API "tasks" (i.e. iou_type) from COCO-format predictions.
        """
        tasks = {"bbox"}
        for pred in predictions:
            if "segmentation" in pred:
                tasks.add("segm")
            if "keypoints" in pred:
                tasks.add("keypoints")
        return sorted(tasks)

    def _eval_predictions(self, predictions, img_ids=None):
        """
        Evaluate predictions. Fill self._results with the metrics of the tasks.
        """
        self._logger.info("Preparing results for COCO format ...")
        coco_results = list(itertools.chain(*[x["instances"] for x in predictions]))
        tasks = self._tasks or self._tasks_from_predictions(coco_results)

        # unmap the category ids for COCO
        if hasattr(self._metadata, "thing_dataset_id_to_contiguous_id"):
            dataset_id_to_contiguous_id = self._metadata.thing_dataset_id_to_contiguous_id
            all_contiguous_ids = list(dataset_id_to_contiguous_id.values())
            num_classes = len(all_contiguous_ids)
            assert min(all_contiguous_ids) == 0 and max(all_contiguous_ids) == num_classes - 1

            reverse_id_mapping = {v: k for k, v in dataset_id_to_contiguous_id.items()}
            for result in coco_results:
                category_id = result["category_id"]
                assert category_id < num_classes, (
                    f"A prediction has class={category_id}, "
                    f"but the dataset only has {num_classes} classes and "
                    f"predicted class id should be in [0, {num_classes - 1}]."
                )
                result["category_id"] = reverse_id_mapping[category_id]

        if self._output_dir:
            file_path = os.path.join(self._output_dir, "coco_instances_results.json")
            self._logger.info("Saving results to {}".format(file_path))
            with PathManager.open(file_path, "w") as f:
                f.write(json.dumps(coco_results))
                f.flush()

        if not self._do_evaluation:
            self._logger.info("Annotations are not available for evaluation.")
            return

        self._logger.info(
            "Evaluating predictions with {} COCO API...".format(
                "unofficial" if self._use_fast_impl else "official"
            )
        )
        for task in sorted(tasks):
            assert task in {"bbox", "segm", "keypoints"}, f"Got unknown task: {task}!"
            coco_eval = (
                _evaluate_predictions_on_coco(
                    self._coco_api,
                    coco_results,
                    task,
                    kpt_oks_sigmas=self._kpt_oks_sigmas,
                    cocoeval_fn=COCOeval_opt if self._use_fast_impl else COCOeval,
                    img_ids=img_ids,
                    max_dets_per_image=self._max_dets_per_image,
                )
                if len(coco_results) > 0
                else None  # cocoapi does not handle empty results very well
            )

            res = self._derive_coco_results(
                coco_eval, task, class_names=self._metadata.get("thing_classes")
            )
            self._results[task] = res

    def _eval_box_proposals(self, predictions):
        """
        Evaluate the box proposals in predictions.
        Fill self._results with the metrics for "box_proposals" task.
        """
        if self._output_dir:
            # Saving generated box proposals to file.
            # Predicted box_proposals are in XYXY_ABS mode.
            bbox_mode = BoxMode.XYXY_ABS.value
            ids, boxes, objectness_logits = [], [], []
            for prediction in predictions:
                ids.append(prediction["image_id"])
                boxes.append(prediction["proposals"].proposal_boxes.tensor.numpy())
                objectness_logits.append(prediction["proposals"].objectness_logits.numpy())

            proposal_data = {
                "boxes": boxes,
                "objectness_logits": objectness_logits,
                "ids": ids,
                "bbox_mode": bbox_mode,
            }
            with PathManager.open(os.path.join(self._output_dir, "box_proposals.pkl"), "wb") as f:
                pickle.dump(proposal_data, f)

        if not self._do_evaluation:
            self._logger.info("Annotations are not available for evaluation.")
            return

        self._logger.info("Evaluating bbox proposals ...")
        res = {}
        areas = {"all": "", "small": "s", "medium": "m", "large": "l"}
        for limit in [100, 1000]:
            for area, suffix in areas.items():
                stats = _evaluate_box_proposals(predictions, self._coco_api, area=area, limit=limit)
                key = "AR{}@{:d}".format(suffix, limit)
                res[key] = float(stats["ar"].item() * 100)
        self._logger.info("Proposal metrics: \n" + create_small_table(res))
        self._results["box_proposals"] = res

    def _derive_coco_results(self, coco_eval, iou_type, class_names=None):
        """
        Derive the desired score numbers from summarized COCOeval.

        Args:
            coco_eval (None or COCOEval): None represents no predictions from model.
            iou_type (str):
            class_names (None or list[str]): if provided, will use it to predict
                per-category AP.

        Returns:
            a dict of {metric name: score}
        """

        metrics = {
            "bbox": ["AP", "AP50", "AP75", "APs", "APm", "APl"],
            "segm": ["AP", "AP50", "AP75", "APs", "APm", "APl"],
            "keypoints": ["AP", "AP50", "AP75", "APm", "APl"],
        }[iou_type]

        if coco_eval is None:
            self._logger.warn("No predictions from the model!")
            return {metric: float("nan") for metric in metrics}

        # the standard metrics
        results = {
            metric: float(coco_eval.stats[idx] * 100 if coco_eval.stats[idx] >= 0 else "nan")
            for idx, metric in enumerate(metrics)
        }
        self._logger.info(
            "Evaluation results for {}: \n".format(iou_type) + create_small_table(results)
        )
        if not np.isfinite(sum(results.values())):
            self._logger.info("Some metrics cannot be computed and is shown as NaN.")

        if class_names is None or len(class_names) <= 1:
            return results
        # Compute per-category AP
        # from https://github.com/facebookresearch/Detectron/blob/a6a835f5b8208c45d0dce217ce9bbda915f44df7/detectron/datasets/json_dataset_evaluator.py#L222-L252 # noqa
        precisions = coco_eval.eval["precision"]
        # precision has dims (iou, recall, cls, area range, max dets)
        assert len(class_names) == precisions.shape[2]

        results_per_category = []
        for idx, name in enumerate(class_names):
            # area range index 0: all area ranges
            # max dets index -1: typically 100 per image
            precision = precisions[:, :, idx, 0, -1]
            precision = precision[precision > -1]
            ap = np.mean(precision) if precision.size else float("nan")
            results_per_category.append(("{}".format(name), float(ap * 100)))

        # tabulate it
        N_COLS = min(6, len(results_per_category) * 2)
        results_flatten = list(itertools.chain(*results_per_category))
        results_2d = itertools.zip_longest(*[results_flatten[i::N_COLS] for i in range(N_COLS)])
        table = tabulate(
            results_2d,
            tablefmt="pipe",
            floatfmt=".3f",
            headers=["category", "AP"] * (N_COLS // 2),
            numalign="left",
        )
        self._logger.info("Per-category {} AP: \n".format(iou_type) + table)

        results.update({"AP-" + name: ap for name, ap in results_per_category})
        return results


def instances_to_coco_json(instances, img_id):
    """
    Dump an "Instances" object to a COCO-format json that's used for evaluation.

    Args:
        instances (Instances):
        img_id (int): the image id

    Returns:
        list[dict]: list of json annotations in COCO format.
    """
    num_instance = len(instances)
    if num_instance == 0:
        return []

    boxes = instances.pred_boxes.tensor.numpy()
    boxes = BoxMode.convert(boxes, BoxMode.XYXY_ABS, BoxMode.XYWH_ABS)
    boxes = boxes.tolist()
    scores = instances.scores.tolist()
    classes = instances.pred_classes.tolist()

    has_mask = instances.has("pred_masks")
    if has_mask:
        # use RLE to encode the masks, because they are too large and takes memory
        # since this evaluator stores outputs of the entire dataset
        rles = [
            mask_util.encode(np.array(mask[:, :, None], order="F", dtype="uint8"))[0]
            for mask in instances.pred_masks
        ]
        for rle in rles:
            # "counts" is an array encoded by mask_util as a byte-stream. Python3's
            # json writer which always produces strings cannot serialize a bytestream
            # unless you decode it. Thankfully, utf-8 works out (which is also what
            # the pycocotools/_mask.pyx does).
            rle["counts"] = rle["counts"].decode("utf-8")

    has_keypoints = instances.has("pred_keypoints")
    if has_keypoints:
        keypoints = instances.pred_keypoints

    results = []
    for k in range(num_instance):
        result = {
            "image_id": img_id,
            "category_id": classes[k],
            "bbox": boxes[k],
            "score": scores[k],
        }
        if has_mask:
            result["segmentation"] = rles[k]
        if has_keypoints:
            # In COCO annotations,
            # keypoints coordinates are pixel indices.
            # However our predictions are floating point coordinates.
            # Therefore we subtract 0.5 to be consistent with the annotation format.
            # This is the inverse of data loading logic in `datasets/coco.py`.
            keypoints[k][:, :2] -= 0.5
            result["keypoints"] = keypoints[k].flatten().tolist()
        results.append(result)
    return results


# inspired from Detectron:
# https://github.com/facebookresearch/Detectron/blob/a6a835f5b8208c45d0dce217ce9bbda915f44df7/detectron/datasets/json_dataset_evaluator.py#L255 # noqa
def _evaluate_box_proposals(dataset_predictions, coco_api, thresholds=None, area="all", limit=None):
    """
    Evaluate detection proposal recall metrics. This function is a much
    faster alternative to the official COCO API recall evaluation code. However,
    it produces slightly different results.
    """
    # Record max overlap value for each gt box
    # Return vector of overlap values
    areas = {
        "all": 0,
        "small": 1,
        "medium": 2,
        "large": 3,
        "96-128": 4,
        "128-256": 5,
        "256-512": 6,
        "512-inf": 7,
    }
    area_ranges = [
        [0**2, 1e5**2],  # all
        [0**2, 32**2],  # small
        [32**2, 96**2],  # medium
        [96**2, 1e5**2],  # large
        [96**2, 128**2],  # 96-128
        [128**2, 256**2],  # 128-256
        [256**2, 512**2],  # 256-512
        [512**2, 1e5**2],
    ]  # 512-inf
    assert area in areas, "Unknown area range: {}".format(area)
    area_range = area_ranges[areas[area]]
    gt_overlaps = []
    num_pos = 0

    for prediction_dict in dataset_predictions:
        predictions = prediction_dict["proposals"]

        # sort predictions in descending order
        # TODO maybe remove this and make it explicit in the documentation
        inds = predictions.objectness_logits.sort(descending=True)[1]
        predictions = predictions[inds]

        ann_ids = coco_api.getAnnIds(imgIds=prediction_dict["image_id"])
        anno = coco_api.loadAnns(ann_ids)
        gt_boxes = [
            BoxMode.convert(obj["bbox"], BoxMode.XYWH_ABS, BoxMode.XYXY_ABS)
            for obj in anno
            if obj["iscrowd"] == 0
        ]
        gt_boxes = torch.as_tensor(gt_boxes).reshape(-1, 4)  # guard against no boxes
        gt_boxes = Boxes(gt_boxes)
        gt_areas = torch.as_tensor([obj["area"] for obj in anno if obj["iscrowd"] == 0])

        if len(gt_boxes) == 0 or len(predictions) == 0:
            continue

        valid_gt_inds = (gt_areas >= area_range[0]) & (gt_areas <= area_range[1])
        gt_boxes = gt_boxes[valid_gt_inds]

        num_pos += len(gt_boxes)

        if len(gt_boxes) == 0:
            continue

        if limit is not None and len(predictions) > limit:
            predictions = predictions[:limit]

        overlaps = pairwise_iou(predictions.proposal_boxes, gt_boxes)

        _gt_overlaps = torch.zeros(len(gt_boxes))
        for j in range(min(len(predictions), len(gt_boxes))):
            # find which proposal box maximally covers each gt box
            # and get the iou amount of coverage for each gt box
            max_overlaps, argmax_overlaps = overlaps.max(dim=0)

            # find which gt box is 'best' covered (i.e. 'best' = most iou)
            gt_ovr, gt_ind = max_overlaps.max(dim=0)
            assert gt_ovr >= 0
            # find the proposal box that covers the best covered gt box
            box_ind = argmax_overlaps[gt_ind]
            # record the iou coverage of this gt box
            _gt_overlaps[j] = overlaps[box_ind, gt_ind]
            assert _gt_overlaps[j] == gt_ovr
            # mark the proposal box and the gt box as used
            overlaps[box_ind, :] = -1
            overlaps[:, gt_ind] = -1

        # append recorded iou coverage level
        gt_overlaps.append(_gt_overlaps)
    gt_overlaps = (
        torch.cat(gt_overlaps, dim=0) if len(gt_overlaps) else torch.zeros(0, dtype=torch.float32)
    )
    gt_overlaps, _ = torch.sort(gt_overlaps)

    if thresholds is None:
        step = 0.05
        thresholds = torch.arange(0.5, 0.95 + 1e-5, step, dtype=torch.float32)
    recalls = torch.zeros_like(thresholds)
    # compute recall for each iou threshold
    for i, t in enumerate(thresholds):
        recalls[i] = (gt_overlaps >= t).float().sum() / float(num_pos)
    # ar = 2 * np.trapz(recalls, thresholds)
    ar = recalls.mean()
    return {
        "ar": ar,
        "recalls": recalls,
        "thresholds": thresholds,
        "gt_overlaps": gt_overlaps,
        "num_pos": num_pos,
    }


def _evaluate_predictions_on_coco(
    coco_gt,
    coco_results,
    iou_type,
    kpt_oks_sigmas=None,
    cocoeval_fn=COCOeval_opt,
    img_ids=None,
    max_dets_per_image=None,
):
    """
    Evaluate the coco results using COCOEval API.
    """
    assert len(coco_results) > 0

    if iou_type == "segm":
        coco_results = copy.deepcopy(coco_results)
        # When evaluating mask AP, if the results contain bbox, cocoapi will
        # use the box area as the area of the instance, instead of the mask area.
        # This leads to a different definition of small/medium/large.
        # We remove the bbox field to let mask AP use mask area.
        for c in coco_results:
            c.pop("bbox", None)

    coco_dt = coco_gt.loadRes(coco_results)
    coco_eval = cocoeval_fn(coco_gt, coco_dt, iou_type)
    # For COCO, the default max_dets_per_image is [1, 10, 100].
    if max_dets_per_image is None:
        max_dets_per_image = [1, 10, 100]  # Default from COCOEval
    else:
        assert (
            len(max_dets_per_image) >= 3
        ), "COCOeval requires maxDets (and max_dets_per_image) to have length at least 3"
        # In the case that user supplies a custom input for max_dets_per_image,
        # apply COCOevalMaxDets to evaluate AP with the custom input.
        if max_dets_per_image[2] != 100:
            coco_eval = COCOevalMaxDets(coco_gt, coco_dt, iou_type)
    if iou_type != "keypoints":
        coco_eval.params.maxDets = max_dets_per_image

    if img_ids is not None:
        coco_eval.params.imgIds = img_ids

    if iou_type == "keypoints":
        # Use the COCO default keypoint OKS sigmas unless overrides are specified
        if kpt_oks_sigmas:
            assert hasattr(coco_eval.params, "kpt_oks_sigmas"), "pycocotools is too old!"
            coco_eval.params.kpt_oks_sigmas = np.array(kpt_oks_sigmas)
        # COCOAPI requires every detection and every gt to have keypoints, so
        # we just take the first entry from both
        num_keypoints_dt = len(coco_results[0]["keypoints"]) // 3
        num_keypoints_gt = len(next(iter(coco_gt.anns.values()))["keypoints"]) // 3
        num_keypoints_oks = len(coco_eval.params.kpt_oks_sigmas)
        assert num_keypoints_oks == num_keypoints_dt == num_keypoints_gt, (
            f"[COCOEvaluator] Prediction contain {num_keypoints_dt} keypoints. "
            f"Ground truth contains {num_keypoints_gt} keypoints. "
            f"The length of cfg.TEST.KEYPOINT_OKS_SIGMAS is {num_keypoints_oks}. "
            "They have to agree with each other. For meaning of OKS, please refer to "
            "http://cocodataset.org/#keypoints-eval."
        )

    coco_eval.evaluate()
    coco_eval.accumulate()
    coco_eval.summarize()

    return coco_eval


class COCOevalMaxDets(COCOeval):
    """
    Modified version of COCOeval for evaluating AP with a custom
    maxDets (by default for COCO, maxDets is 100)
    """

    def summarize(self):
        """
        Compute and display summary metrics for evaluation results given
        a custom value for  max_dets_per_image
        """

        def _summarize(ap=1, iouThr=None, areaRng="all", maxDets=100):
            p = self.params
            iStr = " {:<18} {} @[ IoU={:<9} | area={:>6s} | maxDets={:>3d} ] = {:0.3f}"
            titleStr = "Average Precision" if ap == 1 else "Average Recall"
            typeStr = "(AP)" if ap == 1 else "(AR)"
            iouStr = (
                "{:0.2f}:{:0.2f}".format(p.iouThrs[0], p.iouThrs[-1])
                if iouThr is None
                else "{:0.2f}".format(iouThr)
            )

            aind = [i for i, aRng in enumerate(p.areaRngLbl) if aRng == areaRng]
            mind = [i for i, mDet in enumerate(p.maxDets) if mDet == maxDets]
            if ap == 1:
                # dimension of precision: [TxRxKxAxM]
                s = self.eval["precision"]
                # IoU
                if iouThr is not None:
                    t = np.where(iouThr == p.iouThrs)[0]
                    s = s[t]
                s = s[:, :, :, aind, mind]
            else:
                # dimension of recall: [TxKxAxM]
                s = self.eval["recall"]
                if iouThr is not None:
                    t = np.where(iouThr == p.iouThrs)[0]
                    s = s[t]
                s = s[:, :, aind, mind]
            if len(s[s > -1]) == 0:
                mean_s = -1
            else:
                mean_s = np.mean(s[s > -1])
            print(iStr.format(titleStr, typeStr, iouStr, areaRng, maxDets, mean_s))
            return mean_s

        def _summarizeDets():
            stats = np.zeros((12,))
            # Evaluate AP using the custom limit on maximum detections per image
            stats[0] = _summarize(1, maxDets=self.params.maxDets[2])
            stats[1] = _summarize(1, iouThr=0.5, maxDets=self.params.maxDets[2])
            stats[2] = _summarize(1, iouThr=0.75, maxDets=self.params.maxDets[2])
            stats[3] = _summarize(1, areaRng="small", maxDets=self.params.maxDets[2])
            stats[4] = _summarize(1, areaRng="medium", maxDets=self.params.maxDets[2])
            stats[5] = _summarize(1, areaRng="large", maxDets=self.params.maxDets[2])
            stats[6] = _summarize(0, maxDets=self.params.maxDets[0])
            stats[7] = _summarize(0, maxDets=self.params.maxDets[1])
            stats[8] = _summarize(0, maxDets=self.params.maxDets[2])
            stats[9] = _summarize(0, areaRng="small", maxDets=self.params.maxDets[2])
            stats[10] = _summarize(0, areaRng="medium", maxDets=self.params.maxDets[2])
            stats[11] = _summarize(0, areaRng="large", maxDets=self.params.maxDets[2])
            return stats

        def _summarizeKps():
            stats = np.zeros((10,))
            stats[0] = _summarize(1, maxDets=20)
            stats[1] = _summarize(1, maxDets=20, iouThr=0.5)
            stats[2] = _summarize(1, maxDets=20, iouThr=0.75)
            stats[3] = _summarize(1, maxDets=20, areaRng="medium")
            stats[4] = _summarize(1, maxDets=20, areaRng="large")
            stats[5] = _summarize(0, maxDets=20)
            stats[6] = _summarize(0, maxDets=20, iouThr=0.5)
            stats[7] = _summarize(0, maxDets=20, iouThr=0.75)
            stats[8] = _summarize(0, maxDets=20, areaRng="medium")
            stats[9] = _summarize(0, maxDets=20, areaRng="large")
            return stats

        if not self.eval:
            raise Exception("Please run accumulate() first")
        iouType = self.params.iouType
        if iouType == "segm" or iouType == "bbox":
            summarize = _summarizeDets
        elif iouType == "keypoints":
            summarize = _summarizeKps
        self.stats = summarize()

    def __str__(self):
        self.summarize()