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owocr/manga_ocr_dev/synthetic_data_generator/generator.py
2022-02-09 20:39:37 +01:00

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import budou
import numpy as np
import pandas as pd
from manga_ocr_dev.env import ASSETS_PATH, FONTS_ROOT
from manga_ocr_dev.synthetic_data_generator.renderer import Renderer
from manga_ocr_dev.synthetic_data_generator.utils import get_font_meta, get_charsets, is_ascii, is_kanji
class SyntheticDataGenerator:
def __init__(self):
self.vocab, self.hiragana, self.katakana = get_charsets()
self.len_to_p = pd.read_csv(ASSETS_PATH / 'len_to_p.csv')
self.parser = budou.get_parser('tinysegmenter')
self.fonts_df, self.font_map = get_font_meta()
self.font_labels, self.font_p = self.get_font_labels_prob()
self.renderer = Renderer()
def process(self, text=None, override_css_params=None):
"""
Generate image, text pair. Use source text if provided, otherwise generate random text.
"""
if override_css_params is None:
override_css_params = {}
if text is None:
# if using random text, choose font first,
# and then generate text using only characters supported by that font
if 'font_path' not in override_css_params:
font_path = self.get_random_font()
vocab = self.font_map[font_path]
override_css_params['font_path'] = font_path
else:
font_path = override_css_params['font_path']
vocab = self.font_map[font_path]
words = self.get_random_words(vocab)
else:
text = text.replace(' ', ' ')
text = text.replace('', '...')
words = self.split_into_words(text)
lines = self.words_to_lines(words)
text_gt = '\n'.join(lines)
if 'font_path' not in override_css_params:
override_css_params['font_path'] = self.get_random_font(text_gt)
font_path = override_css_params.get('font_path')
if font_path:
vocab = self.font_map.get(font_path)
# remove unsupported characters
lines = [''.join([c for c in line if c in vocab]) for line in lines]
text_gt = '\n'.join(lines)
else:
vocab = None
if np.random.random() < 0.5:
word_prob = np.random.choice([0.33, 1.0], p=[0.3, 0.7])
lines = [self.add_random_furigana(line, word_prob, vocab) for line in lines]
img, params = self.renderer.render(lines, override_css_params)
return img, text_gt, params
def get_random_words(self, vocab):
vocab = list(vocab)
max_text_len = np.random.choice(self.len_to_p.len, p=self.len_to_p.p)
words = []
text_len = 0
while True:
word = ''.join(np.random.choice(vocab, np.random.randint(1, 4)))
words.append(word)
text_len += len(word)
if text_len + len(word) >= max_text_len:
break
return words
def split_into_words(self, text):
max_text_len = np.random.choice(self.len_to_p.len, p=self.len_to_p.p)
words = []
text_len = 0
for chunk in self.parser.parse(text)['chunks']:
words.append(chunk.word)
text_len += len(chunk.word)
if text_len + len(chunk.word) >= max_text_len:
break
return words
def words_to_lines(self, words):
text = ''.join(words)
max_num_lines = 10
min_line_len = len(text) // max_num_lines
max_line_len = 20
max_line_len = np.clip(np.random.poisson(6), min_line_len, max_line_len)
lines = []
line = ''
for word in words:
line += word
if len(line) >= max_line_len:
lines.append(line)
line = ''
if line:
lines.append(line)
return lines
def add_random_furigana(self, line, word_prob=1.0, vocab=None):
if vocab is None:
vocab = self.vocab
else:
vocab = list(vocab)
processed = ''
kanji_group = ''
ascii_group = ''
for i, c in enumerate(line):
if is_kanji(c):
c_type = 'kanji'
kanji_group += c
elif is_ascii(c):
c_type = 'ascii'
ascii_group += c
else:
c_type = 'other'
if c_type != 'kanji' or i == len(line) - 1:
if kanji_group:
if np.random.uniform() < word_prob:
furigana_len = int(np.clip(np.random.normal(1.5, 0.5), 1, 4) * len(kanji_group))
char_source = np.random.choice(['hiragana', 'katakana', 'all'], p=[0.8, 0.15, 0.05])
char_source = {
'hiragana': self.hiragana,
'katakana': self.katakana,
'all': vocab
}[char_source]
furigana = ''.join(np.random.choice(char_source, furigana_len))
processed += f'<ruby>{kanji_group}<rt>{furigana}</rt></ruby>'
else:
processed += kanji_group
kanji_group = ''
if c_type != 'ascii' or i == len(line) - 1:
if ascii_group:
if len(ascii_group) <= 3 and np.random.uniform() < 0.7:
processed += f'<span style="text-combine-upright: all">{ascii_group}</span>'
else:
processed += ascii_group
ascii_group = ''
if c_type == 'other':
processed += c
return processed
def is_font_supporting_text(self, font_path, text):
chars = self.font_map[font_path]
for c in text:
if c.isspace():
continue
if c not in chars:
return False
return True
def get_font_labels_prob(self):
labels = {
'common': 0.2,
'regular': 0.75,
'special': 0.05,
}
labels = {k: labels[k] for k in self.fonts_df.label.unique()}
p = np.array(list(labels.values()))
p = p / p.sum()
labels = list(labels.keys())
return labels, p
def get_random_font(self, text=None):
label = np.random.choice(self.font_labels, p=self.font_p)
df = self.fonts_df[self.fonts_df.label == label]
if text is None:
return df.sample(1).iloc[0].font_path
valid_mask = df.font_path.apply(lambda x: self.is_font_supporting_text(x, text))
if not valid_mask.any():
# if text contains characters not supported by any font, just pick some of the more capable fonts
valid_mask = (df.num_chars >= 4000)
return str(FONTS_ROOT / df[valid_mask].sample(1).iloc[0].font_path)