modified det reader

ppocr/data/det/dataset_traversal.py

@@ -13,6 +13,7 @@
 #limitations under the License.
 
 import os
+import sys
 import math
 import random
 import functools
@@ -42,6 +43,10 @@ class TrainReader(object):
             img_num = len(label_infor_list)
             img_id_list = list(range(img_num))
             random.shuffle(img_id_list)
+            if sys.platform == "win32":
+                print("multiprocess is not fully compatible with Windows."
+                      "num_workers will be 1.")
+                self.num_workers = 1
             for img_id in range(process_id, img_num, self.num_workers):
                 label_infor = label_infor_list[img_id_list[img_id]]
                 outs = self.process(label_infor)