From ddbfbfcddc5b56de0a1bf960c9acaaf8fc2fc461 Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Tue, 9 Nov 2021 17:16:59 +0800
Subject: [PATCH 1/8] first version

---
 .../api_wrappers/panoptic_evaluation.py       | 156 ++++++++++++++++++
 mmdet/datasets/custom.py                      |  24 ++-
 mmdet/datasets/pipelines/loading.py           |  10 +-
 3 files changed, 173 insertions(+), 17 deletions(-)
 create mode 100644 mmdet/datasets/api_wrappers/panoptic_evaluation.py

diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
new file mode 100644
index 00000000000..2b380a5bdb7
--- /dev/null
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -0,0 +1,156 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+# This file supports `file_client` for panopticapi
+import multiprocessing
+import os
+
+import mmcv
+import numpy as np
+
+try:
+    from panopticapi.evaluation import PQStat, VOID, OFFSET
+    from panopticapi.utils import rgb2id
+except ImportError:
+    PQStat = None
+    rgb2id = None
+    VOID = 0
+    OFFSET = 256 * 256 * 256
+
+
+def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
+                           categories, file_client):
+    if PQStat is None:
+        raise RuntimeError(
+            'panopticapi is not installed, please install it by: '
+            'pip install git+https://github.com/cocodataset/'
+            'panopticapi.git.')
+    pq_stat = PQStat()
+
+    idx = 0
+    for gt_ann, pred_ann in annotation_set:
+        if idx % 100 == 0:
+            print('Core: {}, {} from {} images processed'.format(
+                proc_id, idx, len(annotation_set)))
+        idx += 1
+        img_bytes = file_client.get(
+            os.path.join(gt_folder, gt_ann['file_name']))
+        pan_gt = mmcv.imfrombytes(
+            img_bytes, flag='color', channel_order='rgb').squeeze()
+        pan_gt = rgb2id(pan_gt)
+
+        pan_pred = mmcv.imread(
+            os.path.join(pred_folder, pred_ann['file_name']),
+            flag='color',
+            channel_order='rgb').squeeze()
+        pan_pred = rgb2id(pan_pred)
+
+        gt_segms = {el['id']: el for el in gt_ann['segments_info']}
+        pred_segms = {el['id']: el for el in pred_ann['segments_info']}
+
+        # predicted segments area calculation + prediction sanity checks
+        pred_labels_set = set(el['id'] for el in pred_ann['segments_info'])
+        labels, labels_cnt = np.unique(pan_pred, return_counts=True)
+        for label, label_cnt in zip(labels, labels_cnt):
+            if label not in pred_segms:
+                if label == VOID:
+                    continue
+                raise KeyError(
+                    'In the image with ID {} segment with ID {} is '
+                    'presented in PNG and not presented in JSON.'.format(
+                        gt_ann['image_id'], label))
+            pred_segms[label]['area'] = label_cnt
+            pred_labels_set.remove(label)
+            if pred_segms[label]['category_id'] not in categories:
+                raise KeyError(
+                    'In the image with ID {} segment with ID {} has '
+                    'unknown category_id {}.'.format(
+                        gt_ann['image_id'], label,
+                        pred_segms[label]['category_id']))
+        if len(pred_labels_set) != 0:
+            raise KeyError(
+                'In the image with ID {} the following segment IDs {} '
+                'are presented in JSON and not presented in PNG.'.format(
+                    gt_ann['image_id'], list(pred_labels_set)))
+
+        # confusion matrix calculation
+        pan_gt_pred = pan_gt.astype(np.uint64) * OFFSET + pan_pred.astype(
+            np.uint64)
+        gt_pred_map = {}
+        labels, labels_cnt = np.unique(pan_gt_pred, return_counts=True)
+        for label, intersection in zip(labels, labels_cnt):
+            gt_id = label // OFFSET
+            pred_id = label % OFFSET
+            gt_pred_map[(gt_id, pred_id)] = intersection
+
+        # count all matched pairs
+        gt_matched = set()
+        pred_matched = set()
+        for label_tuple, intersection in gt_pred_map.items():
+            gt_label, pred_label = label_tuple
+            if gt_label not in gt_segms:
+                continue
+            if pred_label not in pred_segms:
+                continue
+            if gt_segms[gt_label]['iscrowd'] == 1:
+                continue
+            if gt_segms[gt_label]['category_id'] != pred_segms[pred_label][
+                    'category_id']:
+                continue
+
+            union = pred_segms[pred_label]['area'] + gt_segms[gt_label][
+                'area'] - intersection - gt_pred_map.get((VOID, pred_label), 0)
+            iou = intersection / union
+            if iou > 0.5:
+                pq_stat[gt_segms[gt_label]['category_id']].tp += 1
+                pq_stat[gt_segms[gt_label]['category_id']].iou += iou
+                gt_matched.add(gt_label)
+                pred_matched.add(pred_label)
+
+        # count false positives
+        crowd_labels_dict = {}
+        for gt_label, gt_info in gt_segms.items():
+            if gt_label in gt_matched:
+                continue
+            # crowd segments are ignored
+            if gt_info['iscrowd'] == 1:
+                crowd_labels_dict[gt_info['category_id']] = gt_label
+                continue
+            pq_stat[gt_info['category_id']].fn += 1
+
+        # count false positives
+        for pred_label, pred_info in pred_segms.items():
+            if pred_label in pred_matched:
+                continue
+            # intersection of the segment with VOID
+            intersection = gt_pred_map.get((VOID, pred_label), 0)
+            # plus intersection with corresponding CROWD region if it exists
+            if pred_info['category_id'] in crowd_labels_dict:
+                intersection += gt_pred_map.get(
+                    (crowd_labels_dict[pred_info['category_id']], pred_label),
+                    0)
+            # predicted segment is ignored if more than half of
+            # the segment correspond to VOID and CROWD regions
+            if intersection / pred_info['area'] > 0.5:
+                continue
+            pq_stat[pred_info['category_id']].fp += 1
+    print('Core: {}, all {} images processed'.format(proc_id,
+                                                     len(annotation_set)))
+    return pq_stat
+
+
+def pq_compute_multi_core(matched_annotations_list, gt_folder, pred_folder,
+                          categories, file_client):
+    cpu_num = multiprocessing.cpu_count()
+    annotations_split = np.array_split(matched_annotations_list, cpu_num)
+    print('Number of cores: {}, images per core: {}'.format(
+        cpu_num, len(annotations_split[0])))
+    workers = multiprocessing.Pool(processes=cpu_num)
+    processes = []
+    for proc_id, annotation_set in enumerate(annotations_split):
+        p = workers.apply_async(pq_compute_single_core,
+                                (proc_id, annotation_set, gt_folder,
+                                 pred_folder, categories, file_client))
+        processes.append(p)
+    pq_stat = PQStat()
+    for p in processes:
+        pq_stat += p.get()
+    return pq_stat
diff --git a/mmdet/datasets/custom.py b/mmdet/datasets/custom.py
index 0e82fa396ad..eea1453364d 100644
--- a/mmdet/datasets/custom.py
+++ b/mmdet/datasets/custom.py
@@ -63,7 +63,8 @@ def __init__(self,
                  seg_prefix=None,
                  proposal_file=None,
                  test_mode=False,
-                 filter_empty_gt=True):
+                 filter_empty_gt=True,
+                 file_client_args=dict(backend='disk')):
         self.ann_file = ann_file
         self.data_root = data_root
         self.img_prefix = img_prefix
@@ -72,24 +73,31 @@ def __init__(self,
         self.test_mode = test_mode
         self.filter_empty_gt = filter_empty_gt
         self.CLASSES = self.get_classes(classes)
+        self.file_client = mmcv.FileClient(**file_client_args)
 
         # join paths if data_root is specified
         if self.data_root is not None:
             if not osp.isabs(self.ann_file):
-                self.ann_file = osp.join(self.data_root, self.ann_file)
+                self.ann_file = self.file_client.join_path(
+                    self.data_root, self.ann_file)
             if not (self.img_prefix is None or osp.isabs(self.img_prefix)):
-                self.img_prefix = osp.join(self.data_root, self.img_prefix)
+                self.img_prefix = self.file_client.join_path(
+                    self.data_root, self.img_prefix)
             if not (self.seg_prefix is None or osp.isabs(self.seg_prefix)):
-                self.seg_prefix = osp.join(self.data_root, self.seg_prefix)
+                self.seg_prefix = self.file_client.join_path(
+                    self.data_root, self.seg_prefix)
             if not (self.proposal_file is None
                     or osp.isabs(self.proposal_file)):
-                self.proposal_file = osp.join(self.data_root,
-                                              self.proposal_file)
+                self.proposal_file = self.file_client.join_path(
+                    self.data_root, self.proposal_file)
         # load annotations (and proposals)
-        self.data_infos = self.load_annotations(self.ann_file)
+        with self.file_client.get_local_path(self.ann_file) as local_path:
+            self.data_infos = self.load_annotations(local_path)
 
         if self.proposal_file is not None:
-            self.proposals = self.load_proposals(self.proposal_file)
+            with self.file_client.get_local_path(
+                    self.proposal_file) as local_path:
+                self.proposals = self.load_proposals(local_path)
         else:
             self.proposals = None
 
diff --git a/mmdet/datasets/pipelines/loading.py b/mmdet/datasets/pipelines/loading.py
index 1f8ba37e1a5..a7f1974a025 100644
--- a/mmdet/datasets/pipelines/loading.py
+++ b/mmdet/datasets/pipelines/loading.py
@@ -231,7 +231,7 @@ def __init__(self,
         self.with_seg = with_seg
         self.poly2mask = poly2mask
         self.file_client_args = file_client_args.copy()
-        self.file_client = None
+        self.file_client = mmcv.FileClient(**self.file_client_args)
 
     def _load_bboxes(self, results):
         """Private function to load bounding box annotations.
@@ -344,10 +344,6 @@ def _load_semantic_seg(self, results):
         Returns:
             dict: The dict contains loaded semantic segmentation annotations.
         """
-
-        if self.file_client is None:
-            self.file_client = mmcv.FileClient(**self.file_client_args)
-
         filename = osp.join(results['seg_prefix'],
                             results['ann_info']['seg_map'])
         img_bytes = self.file_client.get(filename)
@@ -438,12 +434,8 @@ def _load_masks_and_semantic_segs(self, results):
             dict: The dict contains loaded mask and semantic segmentation
                 annotations. `BitmapMasks` is used for mask annotations.
         """
-
-        if self.file_client is None:
-            self.file_client = mmcv.FileClient(**self.file_client_args)
         filename = osp.join(results['seg_prefix'],
                             results['ann_info']['seg_map'])
-
         img_bytes = self.file_client.get(filename)
         pan_png = mmcv.imfrombytes(
             img_bytes, flag='color', channel_order='rgb').squeeze()

From d5c834919b99d21df13533db93979cc02514329a Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Thu, 11 Nov 2021 20:28:50 +0800
Subject: [PATCH 2/8] Replace with our api

---
 mmdet/datasets/api_wrappers/__init__.py | 3 ++-
 mmdet/datasets/coco_panoptic.py         | 8 ++++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/mmdet/datasets/api_wrappers/__init__.py b/mmdet/datasets/api_wrappers/__init__.py
index 9bf807107a4..6dc535a113c 100644
--- a/mmdet/datasets/api_wrappers/__init__.py
+++ b/mmdet/datasets/api_wrappers/__init__.py
@@ -1,4 +1,5 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 from .coco_api import COCO, COCOeval
+from .panoptic_evaluation import pq_compute_multi_core
 
-__all__ = ['COCO', 'COCOeval']
+__all__ = ['COCO', 'COCOeval', 'pq_compute_multi_core']
diff --git a/mmdet/datasets/coco_panoptic.py b/mmdet/datasets/coco_panoptic.py
index 36e95950d97..e2b5c636409 100644
--- a/mmdet/datasets/coco_panoptic.py
+++ b/mmdet/datasets/coco_panoptic.py
@@ -8,17 +8,16 @@
 from mmcv.utils import print_log
 from terminaltables import AsciiTable
 
-from .api_wrappers import COCO
+from .api_wrappers import COCO, pq_compute_multi_core
 from .builder import DATASETS
 from .coco import CocoDataset
 
 try:
     import panopticapi
-    from panopticapi.evaluation import pq_compute_multi_core, VOID
+    from panopticapi.evaluation import VOID
     from panopticapi.utils import id2rgb
 except ImportError:
     panopticapi = None
-    pq_compute_multi_core = None
     id2rgb = None
     VOID = None
 
@@ -421,7 +420,8 @@ def evaluate_pan_json(self,
         pred_folder = os.path.join(os.path.dirname(outfile_prefix), 'panoptic')
 
         pq_stat = pq_compute_multi_core(matched_annotations_list, gt_folder,
-                                        pred_folder, self.categories)
+                                        pred_folder, self.categories,
+                                        self.file_client)
 
         metrics = [('All', None), ('Things', True), ('Stuff', False)]
         pq_results = {}

From cae49e01e050b38a7ed7f4179748c762ff1dccf9 Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Fri, 12 Nov 2021 14:59:32 +0800
Subject: [PATCH 3/8] Add copyright

---
 mmdet/datasets/api_wrappers/panoptic_evaluation.py | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
index 2b380a5bdb7..8f83cccdc01 100644
--- a/mmdet/datasets/api_wrappers/panoptic_evaluation.py
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -1,5 +1,9 @@
 # Copyright (c) OpenMMLab. All rights reserved.
-# This file supports `file_client` for panopticapi
+
+# Copyright (c) 2018, Alexander Kirillov
+# This file supports `file_client` for `panopticapi`,
+# the source code is copied from `panopticapi`,
+# only the way to read the gt images is modified.
 import multiprocessing
 import os
 

From fb96094733836d5b5cc2018ea34e2a3207a68fe9 Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Fri, 12 Nov 2021 15:24:27 +0800
Subject: [PATCH 4/8] Move the runtime error to multi_core interface

---
 mmdet/datasets/api_wrappers/panoptic_evaluation.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
index 8f83cccdc01..a83af348595 100644
--- a/mmdet/datasets/api_wrappers/panoptic_evaluation.py
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -22,11 +22,6 @@
 
 def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
                            categories, file_client):
-    if PQStat is None:
-        raise RuntimeError(
-            'panopticapi is not installed, please install it by: '
-            'pip install git+https://github.com/cocodataset/'
-            'panopticapi.git.')
     pq_stat = PQStat()
 
     idx = 0
@@ -143,6 +138,11 @@ def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
 
 def pq_compute_multi_core(matched_annotations_list, gt_folder, pred_folder,
                           categories, file_client):
+    if PQStat is None:
+        raise RuntimeError(
+            'panopticapi is not installed, please install it by: '
+            'pip install git+https://github.com/cocodataset/'
+            'panopticapi.git.')
     cpu_num = multiprocessing.cpu_count()
     annotations_split = np.array_split(matched_annotations_list, cpu_num)
     print('Number of cores: {}, images per core: {}'.format(

From 9197efa381be2ee2cd0fab92fe535b84aa37dfd6 Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Fri, 12 Nov 2021 16:27:37 +0800
Subject: [PATCH 5/8] Add docstring

---
 .../api_wrappers/panoptic_evaluation.py       | 28 ++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
index a83af348595..427e94b80f9 100644
--- a/mmdet/datasets/api_wrappers/panoptic_evaluation.py
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -3,7 +3,7 @@
 # Copyright (c) 2018, Alexander Kirillov
 # This file supports `file_client` for `panopticapi`,
 # the source code is copied from `panopticapi`,
-# only the way to read the gt images is modified.
+# only the way to load the gt images is modified.
 import multiprocessing
 import os
 
@@ -22,6 +22,19 @@
 
 def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
                            categories, file_client):
+    """The single core function to evaluate the metric of Panoptic
+    Segmentation.
+
+    Same as the function with the same name in `panopticapi`. Only the function
+    to load the images is changed to use the file client.
+
+    Args:
+        proc_id (int): The id of the mini process.
+        gt_folder (str): The path of the ground truth images.
+        pred_folder (str): The path of the prediction images.
+        categories (str): The categories of the dataset.
+        file_client (object): The file client of the dataset.
+    """
     pq_stat = PQStat()
 
     idx = 0
@@ -138,6 +151,19 @@ def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
 
 def pq_compute_multi_core(matched_annotations_list, gt_folder, pred_folder,
                           categories, file_client):
+    """Evaluate the metrics of Panoptic Segmentation with multithreading.
+
+    Same as the function with the same name in `panopticapi`.
+
+    Args:
+        matched_annotations_list (list): The matched annotation list. Each
+            element is a tuple of annotations of the same image with the
+            format (gt_anns, pred_anns).
+        gt_folder (str): The path of the ground truth images.
+        pred_folder (str): The path of the prediction images.
+        categories (str): The categories of the dataset.
+        file_client (object): The file client of the dataset.
+    """
     if PQStat is None:
         raise RuntimeError(
             'panopticapi is not installed, please install it by: '

From 18e8d47b1ba280c98fca851e8ce66e2c62a7d5cc Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Mon, 15 Nov 2021 16:04:52 +0800
Subject: [PATCH 6/8] Fix comments

---
 .../api_wrappers/panoptic_evaluation.py       | 35 ++++++++++++++-----
 mmdet/datasets/custom.py                      | 13 +++----
 mmdet/datasets/pipelines/loading.py           | 10 +++++-
 3 files changed, 40 insertions(+), 18 deletions(-)

diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
index 427e94b80f9..86e84c858c2 100644
--- a/mmdet/datasets/api_wrappers/panoptic_evaluation.py
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -20,8 +20,12 @@
     OFFSET = 256 * 256 * 256
 
 
-def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
-                           categories, file_client):
+def pq_compute_single_core(proc_id,
+                           annotation_set,
+                           gt_folder,
+                           pred_folder,
+                           categories,
+                           file_client=None):
     """The single core function to evaluate the metric of Panoptic
     Segmentation.
 
@@ -33,8 +37,13 @@ def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
         gt_folder (str): The path of the ground truth images.
         pred_folder (str): The path of the prediction images.
         categories (str): The categories of the dataset.
-        file_client (object): The file client of the dataset.
+        file_client (object): The file client of the dataset. If None,
+            the backend will be set to `disk`.
     """
+    if file_client is None:
+        file_client_args = dict(backend='disk')
+        file_client = mmcv.FileClient(**file_client_args)
+
     pq_stat = PQStat()
 
     idx = 0
@@ -45,14 +54,13 @@ def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
         idx += 1
         img_bytes = file_client.get(
             os.path.join(gt_folder, gt_ann['file_name']))
-        pan_gt = mmcv.imfrombytes(
-            img_bytes, flag='color', channel_order='rgb').squeeze()
+        pan_gt = mmcv.imfrombytes(img_bytes, flag='color', channel_order='rgb')
         pan_gt = rgb2id(pan_gt)
 
         pan_pred = mmcv.imread(
             os.path.join(pred_folder, pred_ann['file_name']),
             flag='color',
-            channel_order='rgb').squeeze()
+            channel_order='rgb')
         pan_pred = rgb2id(pan_pred)
 
         gt_segms = {el['id']: el for el in gt_ann['segments_info']}
@@ -149,8 +157,11 @@ def pq_compute_single_core(proc_id, annotation_set, gt_folder, pred_folder,
     return pq_stat
 
 
-def pq_compute_multi_core(matched_annotations_list, gt_folder, pred_folder,
-                          categories, file_client):
+def pq_compute_multi_core(matched_annotations_list,
+                          gt_folder,
+                          pred_folder,
+                          categories,
+                          file_client=None):
     """Evaluate the metrics of Panoptic Segmentation with multithreading.
 
     Same as the function with the same name in `panopticapi`.
@@ -162,13 +173,19 @@ def pq_compute_multi_core(matched_annotations_list, gt_folder, pred_folder,
         gt_folder (str): The path of the ground truth images.
         pred_folder (str): The path of the prediction images.
         categories (str): The categories of the dataset.
-        file_client (object): The file client of the dataset.
+        file_client (object): The file client of the dataset. If None,
+            the backend will be set to `disk`.
     """
     if PQStat is None:
         raise RuntimeError(
             'panopticapi is not installed, please install it by: '
             'pip install git+https://github.com/cocodataset/'
             'panopticapi.git.')
+
+    if file_client is None:
+        file_client_args = dict(backend='disk')
+        file_client = mmcv.FileClient(**file_client_args)
+
     cpu_num = multiprocessing.cpu_count()
     annotations_split = np.array_split(matched_annotations_list, cpu_num)
     print('Number of cores: {}, images per core: {}'.format(
diff --git a/mmdet/datasets/custom.py b/mmdet/datasets/custom.py
index eea1453364d..b730ecc2b9e 100644
--- a/mmdet/datasets/custom.py
+++ b/mmdet/datasets/custom.py
@@ -78,18 +78,15 @@ def __init__(self,
         # join paths if data_root is specified
         if self.data_root is not None:
             if not osp.isabs(self.ann_file):
-                self.ann_file = self.file_client.join_path(
-                    self.data_root, self.ann_file)
+                self.ann_file = osp.join(self.data_root, self.ann_file)
             if not (self.img_prefix is None or osp.isabs(self.img_prefix)):
-                self.img_prefix = self.file_client.join_path(
-                    self.data_root, self.img_prefix)
+                self.img_prefix = osp.join(self.data_root, self.img_prefix)
             if not (self.seg_prefix is None or osp.isabs(self.seg_prefix)):
-                self.seg_prefix = self.file_client.join_path(
-                    self.data_root, self.seg_prefix)
+                self.seg_prefix = osp.join(self.data_root, self.seg_prefix)
             if not (self.proposal_file is None
                     or osp.isabs(self.proposal_file)):
-                self.proposal_file = self.file_client.join_path(
-                    self.data_root, self.proposal_file)
+                self.proposal_file = osp.join(self.data_root,
+                                              self.proposal_file)
         # load annotations (and proposals)
         with self.file_client.get_local_path(self.ann_file) as local_path:
             self.data_infos = self.load_annotations(local_path)
diff --git a/mmdet/datasets/pipelines/loading.py b/mmdet/datasets/pipelines/loading.py
index a7f1974a025..4a6e043e8e1 100644
--- a/mmdet/datasets/pipelines/loading.py
+++ b/mmdet/datasets/pipelines/loading.py
@@ -231,7 +231,7 @@ def __init__(self,
         self.with_seg = with_seg
         self.poly2mask = poly2mask
         self.file_client_args = file_client_args.copy()
-        self.file_client = mmcv.FileClient(**self.file_client_args)
+        self.file_client = None
 
     def _load_bboxes(self, results):
         """Private function to load bounding box annotations.
@@ -344,6 +344,10 @@ def _load_semantic_seg(self, results):
         Returns:
             dict: The dict contains loaded semantic segmentation annotations.
         """
+
+        if self.file_client is None:
+            self.file_client = mmcv.FileClient(**self.file_client_args)
+
         filename = osp.join(results['seg_prefix'],
                             results['ann_info']['seg_map'])
         img_bytes = self.file_client.get(filename)
@@ -434,6 +438,10 @@ def _load_masks_and_semantic_segs(self, results):
             dict: The dict contains loaded mask and semantic segmentation
                 annotations. `BitmapMasks` is used for mask annotations.
         """
+
+        if self.file_client is None:
+            self.file_client = mmcv.FileClient(**self.file_client_args)
+
         filename = osp.join(results['seg_prefix'],
                             results['ann_info']['seg_map'])
         img_bytes = self.file_client.get(filename)

From 1ece2e87f978be5e838965ce008b1666b539e9a6 Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Fri, 19 Nov 2021 15:32:01 +0800
Subject: [PATCH 7/8] Add comments

---
 mmdet/datasets/api_wrappers/panoptic_evaluation.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
index 86e84c858c2..b595aaf8f36 100644
--- a/mmdet/datasets/api_wrappers/panoptic_evaluation.py
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -52,11 +52,14 @@ def pq_compute_single_core(proc_id,
             print('Core: {}, {} from {} images processed'.format(
                 proc_id, idx, len(annotation_set)))
         idx += 1
+        # The gt images can be on the local disk or `ceph`, so we use
+        # file_client here.
         img_bytes = file_client.get(
             os.path.join(gt_folder, gt_ann['file_name']))
         pan_gt = mmcv.imfrombytes(img_bytes, flag='color', channel_order='rgb')
         pan_gt = rgb2id(pan_gt)
 
+        # The predictions can only be on the local dist now.
         pan_pred = mmcv.imread(
             os.path.join(pred_folder, pred_ann['file_name']),
             flag='color',

From 8f9df510e087c1174d3768f02d9a824f842fae59 Mon Sep 17 00:00:00 2001
From: AronLin <347630870@qq.com>
Date: Fri, 19 Nov 2021 20:28:41 +0800
Subject: [PATCH 8/8] Add unit test for pq_compute_single_core

---
 mmdet/datasets/api_wrappers/__init__.py       |  6 ++--
 .../api_wrappers/panoptic_evaluation.py       |  6 ++++
 .../test_datasets/test_panoptic_dataset.py    | 32 +++++++++++++++++++
 3 files changed, 42 insertions(+), 2 deletions(-)

diff --git a/mmdet/datasets/api_wrappers/__init__.py b/mmdet/datasets/api_wrappers/__init__.py
index 6dc535a113c..af8557593b6 100644
--- a/mmdet/datasets/api_wrappers/__init__.py
+++ b/mmdet/datasets/api_wrappers/__init__.py
@@ -1,5 +1,7 @@
 # Copyright (c) OpenMMLab. All rights reserved.
 from .coco_api import COCO, COCOeval
-from .panoptic_evaluation import pq_compute_multi_core
+from .panoptic_evaluation import pq_compute_multi_core, pq_compute_single_core
 
-__all__ = ['COCO', 'COCOeval', 'pq_compute_multi_core']
+__all__ = [
+    'COCO', 'COCOeval', 'pq_compute_multi_core', 'pq_compute_single_core'
+]
diff --git a/mmdet/datasets/api_wrappers/panoptic_evaluation.py b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
index b595aaf8f36..1a21fe8f098 100644
--- a/mmdet/datasets/api_wrappers/panoptic_evaluation.py
+++ b/mmdet/datasets/api_wrappers/panoptic_evaluation.py
@@ -40,6 +40,12 @@ def pq_compute_single_core(proc_id,
         file_client (object): The file client of the dataset. If None,
             the backend will be set to `disk`.
     """
+    if PQStat is None:
+        raise RuntimeError(
+            'panopticapi is not installed, please install it by: '
+            'pip install git+https://github.com/cocodataset/'
+            'panopticapi.git.')
+
     if file_client is None:
         file_client_args = dict(backend='disk')
         file_client = mmcv.FileClient(**file_client_args)
diff --git a/tests/test_data/test_datasets/test_panoptic_dataset.py b/tests/test_data/test_datasets/test_panoptic_dataset.py
index 44670f22f07..fd571d219d1 100644
--- a/tests/test_data/test_datasets/test_panoptic_dataset.py
+++ b/tests/test_data/test_datasets/test_panoptic_dataset.py
@@ -5,6 +5,7 @@
 import mmcv
 import numpy as np
 
+from mmdet.datasets.api_wrappers import pq_compute_single_core
 from mmdet.datasets.coco_panoptic import INSTANCE_OFFSET, CocoPanopticDataset
 
 try:
@@ -305,3 +306,34 @@ def test_panoptic_evaluation():
     assert np.isclose(parsed_results['PQ_st'], 82.701)
     assert np.isclose(parsed_results['SQ_st'], 82.701)
     assert np.isclose(parsed_results['RQ_st'], 100.000)
+
+    # test the api wrapper of `pq_compute_single_core`
+    # Codes are copied from `coco_panoptic.py` and modified
+    result_files, _ = dataset.format_results(
+        results, jsonfile_prefix=outfile_prefix)
+
+    imgs = dataset.coco.imgs
+    gt_json = dataset.coco.img_ann_map  # image to annotations
+    gt_json = [{
+        'image_id': k,
+        'segments_info': v,
+        'file_name': imgs[k]['segm_file']
+    } for k, v in gt_json.items()]
+    pred_json = mmcv.load(result_files['panoptic'])
+    pred_json = dict((el['image_id'], el) for el in pred_json['annotations'])
+
+    # match the gt_anns and pred_anns in the same image
+    matched_annotations_list = []
+    for gt_ann in gt_json:
+        img_id = gt_ann['image_id']
+        matched_annotations_list.append((gt_ann, pred_json[img_id]))
+    gt_folder = dataset.seg_prefix
+    pred_folder = osp.join(osp.dirname(outfile_prefix), 'panoptic')
+
+    pq_stat = pq_compute_single_core(0, matched_annotations_list, gt_folder,
+                                     pred_folder, dataset.categories)
+    pq_all = pq_stat.pq_average(dataset.categories, isthing=None)[0]
+    assert np.isclose(pq_all['pq'] * 100, 67.869)
+    assert np.isclose(pq_all['sq'] * 100, 80.898)
+    assert np.isclose(pq_all['rq'] * 100, 83.333)
+    assert pq_all['n'] == 3