Files
TexTeller/texteller/paddleocr/CTCLabelDecode.py
2025-04-19 14:32:28 +00:00

213 lines
7.5 KiB
Python

import os
import re
from pathlib import Path
import numpy as np
class BaseRecLabelDecode(object):
"""Convert between text-label and text-index"""
def __init__(self, character_dict_path=None, use_space_char=False):
cur_path = os.getcwd()
scriptDir = Path(__file__).resolve().parent
os.chdir(scriptDir)
character_dict_path = str(Path(scriptDir / "ppocr_keys_v1.txt"))
self.beg_str = "sos"
self.end_str = "eos"
self.reverse = False
self.character_str = []
if character_dict_path is None:
self.character_str = "0123456789abcdefghijklmnopqrstuvwxyz"
dict_character = list(self.character_str)
else:
with open(character_dict_path, "rb") as fin:
lines = fin.readlines()
for line in lines:
line = line.decode("utf-8").strip("\n").strip("\r\n")
self.character_str.append(line)
if use_space_char:
self.character_str.append(" ")
dict_character = list(self.character_str)
if "arabic" in character_dict_path:
self.reverse = True
dict_character = self.add_special_char(dict_character)
self.dict = {}
for i, char in enumerate(dict_character):
self.dict[char] = i
self.character = dict_character
os.chdir(cur_path)
def pred_reverse(self, pred):
pred_re = []
c_current = ""
for c in pred:
if not bool(re.search("[a-zA-Z0-9 :*./%+-]", c)):
if c_current != "":
pred_re.append(c_current)
pred_re.append(c)
c_current = ""
else:
c_current += c
if c_current != "":
pred_re.append(c_current)
return "".join(pred_re[::-1])
def add_special_char(self, dict_character):
return dict_character
def get_word_info(self, text, selection):
"""
Group the decoded characters and record the corresponding decoded positions.
Args:
text: the decoded text
selection: the bool array that identifies which columns of features are decoded as non-separated characters
Returns:
word_list: list of the grouped words
word_col_list: list of decoding positions corresponding to each character in the grouped word
state_list: list of marker to identify the type of grouping words, including two types of grouping words:
- 'cn': continous chinese characters (e.g., 你好啊)
- 'en&num': continous english characters (e.g., hello), number (e.g., 123, 1.123), or mixed of them connected by '-' (e.g., VGG-16)
The remaining characters in text are treated as separators between groups (e.g., space, '(', ')', etc.).
"""
state = None
word_content = []
word_col_content = []
word_list = []
word_col_list = []
state_list = []
valid_col = np.where(selection)[0]
for c_i, char in enumerate(text):
if "\u4e00" <= char <= "\u9fff":
c_state = "cn"
elif bool(re.search("[a-zA-Z0-9]", char)):
c_state = "en&num"
else:
c_state = "splitter"
if (
char == "."
and state == "en&num"
and c_i + 1 < len(text)
and bool(re.search("[0-9]", text[c_i + 1]))
): # grouping floting number
c_state = "en&num"
if (
char == "-" and state == "en&num"
): # grouping word with '-', such as 'state-of-the-art'
c_state = "en&num"
if state is None:
state = c_state
if state != c_state:
if len(word_content) != 0:
word_list.append(word_content)
word_col_list.append(word_col_content)
state_list.append(state)
word_content = []
word_col_content = []
state = c_state
if state != "splitter":
word_content.append(char)
word_col_content.append(valid_col[c_i])
if len(word_content) != 0:
word_list.append(word_content)
word_col_list.append(word_col_content)
state_list.append(state)
return word_list, word_col_list, state_list
def decode(
self,
text_index,
text_prob=None,
is_remove_duplicate=False,
return_word_box=False,
):
"""convert text-index into text-label."""
result_list = []
ignored_tokens = self.get_ignored_tokens()
batch_size = len(text_index)
for batch_idx in range(batch_size):
selection = np.ones(len(text_index[batch_idx]), dtype=bool)
if is_remove_duplicate:
selection[1:] = text_index[batch_idx][1:] != text_index[batch_idx][:-1]
for ignored_token in ignored_tokens:
selection &= text_index[batch_idx] != ignored_token
char_list = [self.character[text_id] for text_id in text_index[batch_idx][selection]]
if text_prob is not None:
conf_list = text_prob[batch_idx][selection]
else:
conf_list = [1] * len(selection)
if len(conf_list) == 0:
conf_list = [0]
text = "".join(char_list)
if self.reverse: # for arabic rec
text = self.pred_reverse(text)
if return_word_box:
word_list, word_col_list, state_list = self.get_word_info(text, selection)
result_list.append(
(
text,
np.mean(conf_list).tolist(),
[
len(text_index[batch_idx]),
word_list,
word_col_list,
state_list,
],
)
)
else:
result_list.append((text, np.mean(conf_list).tolist()))
return result_list
def get_ignored_tokens(self):
return [0] # for ctc blank
class CTCLabelDecode(BaseRecLabelDecode):
"""Convert between text-label and text-index"""
def __init__(self, character_dict_path=None, use_space_char=False, **kwargs):
super(CTCLabelDecode, self).__init__(character_dict_path, use_space_char)
def __call__(self, preds, label=None, return_word_box=False, *args, **kwargs):
if isinstance(preds, tuple) or isinstance(preds, list):
preds = preds[-1]
assert isinstance(preds, np.ndarray)
preds_idx = preds.argmax(axis=2)
preds_prob = preds.max(axis=2)
text = self.decode(
preds_idx,
preds_prob,
is_remove_duplicate=True,
return_word_box=return_word_box,
)
if return_word_box:
for rec_idx, rec in enumerate(text):
wh_ratio = kwargs["wh_ratio_list"][rec_idx]
max_wh_ratio = kwargs["max_wh_ratio"]
rec[2][0] = rec[2][0] * (wh_ratio / max_wh_ratio)
if label is None:
return text
label = self.decode(label)
return text, label
def add_special_char(self, dict_character):
dict_character = ["blank"] + dict_character
return dict_character