--- a
+++ b/tools/convert_datasets/pascal_context.py
@@ -0,0 +1,87 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import argparse
+import os.path as osp
+from functools import partial
+
+import mmcv
+import numpy as np
+from detail import Detail
+from PIL import Image
+
+_mapping = np.sort(
+    np.array([
+        0, 2, 259, 260, 415, 324, 9, 258, 144, 18, 19, 22, 23, 397, 25, 284,
+        158, 159, 416, 33, 162, 420, 454, 295, 296, 427, 44, 45, 46, 308, 59,
+        440, 445, 31, 232, 65, 354, 424, 68, 326, 72, 458, 34, 207, 80, 355,
+        85, 347, 220, 349, 360, 98, 187, 104, 105, 366, 189, 368, 113, 115
+    ]))
+_key = np.array(range(len(_mapping))).astype('uint8')
+
+
+def generate_labels(img_id, detail, out_dir):
+
+    def _class_to_index(mask, _mapping, _key):
+        # assert the values
+        values = np.unique(mask)
+        for i in range(len(values)):
+            assert (values[i] in _mapping)
+        index = np.digitize(mask.ravel(), _mapping, right=True)
+        return _key[index].reshape(mask.shape)
+
+    mask = Image.fromarray(
+        _class_to_index(detail.getMask(img_id), _mapping=_mapping, _key=_key))
+    filename = img_id['file_name']
+    mask.save(osp.join(out_dir, filename.replace('jpg', 'png')))
+    return osp.splitext(osp.basename(filename))[0]
+
+
+def parse_args():
+    parser = argparse.ArgumentParser(
+        description='Convert PASCAL VOC annotations to mmsegmentation format')
+    parser.add_argument('devkit_path', help='pascal voc devkit path')
+    parser.add_argument('json_path', help='annoation json filepath')
+    parser.add_argument('-o', '--out_dir', help='output path')
+    args = parser.parse_args()
+    return args
+
+
+def main():
+    args = parse_args()
+    devkit_path = args.devkit_path
+    if args.out_dir is None:
+        out_dir = osp.join(devkit_path, 'VOC2010', 'SegmentationClassContext')
+    else:
+        out_dir = args.out_dir
+    json_path = args.json_path
+    mmcv.mkdir_or_exist(out_dir)
+    img_dir = osp.join(devkit_path, 'VOC2010', 'JPEGImages')
+
+    train_detail = Detail(json_path, img_dir, 'train')
+    train_ids = train_detail.getImgs()
+
+    val_detail = Detail(json_path, img_dir, 'val')
+    val_ids = val_detail.getImgs()
+
+    mmcv.mkdir_or_exist(
+        osp.join(devkit_path, 'VOC2010/ImageSets/SegmentationContext'))
+
+    train_list = mmcv.track_progress(
+        partial(generate_labels, detail=train_detail, out_dir=out_dir),
+        train_ids)
+    with open(
+            osp.join(devkit_path, 'VOC2010/ImageSets/SegmentationContext',
+                     'train.txt'), 'w') as f:
+        f.writelines(line + '\n' for line in sorted(train_list))
+
+    val_list = mmcv.track_progress(
+        partial(generate_labels, detail=val_detail, out_dir=out_dir), val_ids)
+    with open(
+            osp.join(devkit_path, 'VOC2010/ImageSets/SegmentationContext',
+                     'val.txt'), 'w') as f:
+        f.writelines(line + '\n' for line in sorted(val_list))
+
+    print('Done!')
+
+
+if __name__ == '__main__':
+    main()