Remove redundant functions

ppocr/data/imaug/label_ops.py

@@ -123,7 +123,7 @@ class BaseRecLabelEncode(object):
                     [sum(text_lengths)] = [text_index_0 + text_index_1 + ... + text_index_(n - 1)]
             length: length of each text. [batch_size]
         """
-        if len(text) > self.max_text_len:
+        if len(text) == 0 or len(text) > self.max_text_len:
             return None
         if self.character_type == "en":
             text = text.lower()
@@ -138,9 +138,6 @@ class BaseRecLabelEncode(object):
             return None
         return text_list
 
-    def get_ignored_tokens(self):
-        return [0]  # for ctc blank
-
 
 class CTCLabelEncode(BaseRecLabelEncode):
     """ Convert between text-label and text-index """
@@ -193,11 +190,6 @@ class AttnLabelEncode(BaseRecLabelEncode):
         text = self.encode(text)
         return text
 
-    def get_ignored_tokens(self):
-        beg_idx = self.get_beg_end_flag_idx("beg")
-        end_idx = self.get_beg_end_flag_idx("end")
-        return [beg_idx, end_idx]
-
     def get_beg_end_flag_idx(self, beg_or_end):
         if beg_or_end == "beg":
             idx = np.array(self.dict[self.beg_str])