add cityscapes dataset

dygraph/datasets/cityscapes.py

+#   Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import os
+
+from paddle.fluid.io import Dataset
+
+from utils.download import download_file_and_uncompress
+
+DATA_HOME = os.path.expanduser('~/.cache/paddle/dataset')
+URL = "https://paddleseg.bj.bcebos.com/dataset/cityscapes.tar"
+
+
+class Cityscapes(Dataset):
+    def __init__(self,
+                 data_dir=None,
+                 transforms=None,
+                 mode='train',
+                 download=True):
+        self.data_dir = data_dir
+        self.transforms = transforms
+        self.file_list = list()
+        self.mode = mode
+        self.num_classes = 19
+
+        if mode.lower() not in ['train', 'eval', 'test']:
+            raise Exception(
+                "mode should be 'train', 'eval' or 'test', but got {}.".format(
+                    mode))
+
+        if self.transforms is None:
+            raise Exception("transform is necessary, but it is None.")
+
+        self.data_dir = data_dir
+        if self.data_dir is None:
+            if not download:
+                raise Exception("data_file not set and auto download disabled.")
+            self.data_dir = download_file_and_uncompress(
+                url=URL, savepath=DATA_HOME, extrapath=DATA_HOME)
+
+        if mode == 'train':
+            file_list = os.path.join(self.data_dir, 'train.list')
+        elif mode == 'eval':
+            file_list = os.path.join(self.data_dir, 'val.list')
+        else:
+            file_list = os.path.join(self.data_dir, 'test.list')
+
+        with open(file_list, 'r') as f:
+            for line in f:
+                items = line.strip().split()
+                if len(items) != 2:
+                    if mode == 'train' or mode == 'eval':
+                        raise Exception(
+                            "File list format incorrect! It should be"
+                            " image_name label_name\\n")
+                    image_path = os.path.join(self.data_dir, items[0])
+                    grt_path = None
+                else:
+                    image_path = os.path.join(self.data_dir, items[0])
+                    grt_path = os.path.join(self.data_dir, items[1])
+                self.file_list.append([image_path, grt_path])
+
+    def __getitem__(self, idx):
+        image_path, grt_path = self.file_list[idx]
+        im, im_info, label = self.transforms(im=image_path, label=grt_path)
+        if self.mode == 'train':
+            return im, label
+        elif self.mode == 'eval':
+            return im, label
+        if self.mode == 'test':
+            return im, im_info, image_path
+
+    def __len__(self):
+        return len(self.file_list)