class OCR(object):
MAX_MODELS = 5
MIN_WIDTH = 10
MIN_HEIGHT = 10
def __init__(self):
# Tesseract language types:
_, self.supported = get_languages()
self.reset_engine('eng')
def language_list(self, languages):
models = [c for c in alpha3(languages) if c in self.supported]
if len(models) > self.MAX_MODELS:
log.warning("Too many models, limit: %s", self.MAX_MODELS)
models = models[:self.MAX_MODELS]
models.append('eng')
return '+'.join(sorted(set(models)))
def reset_engine(self, languages):
if hasattr(self, 'api'):
self.api.Clear()
self.api.End()
self.api = PyTessBaseAPI(lang=languages, oem=OEM.LSTM_ONLY)
def extract_text(self, data, languages=None, mode=PSM.AUTO_OSD):
"""Extract text from a binary string of data."""
languages = self.language_list(languages)
if languages != self.api.GetInitLanguagesAsString():
self.reset_engine(languages)
try:
image = Image.open(BytesIO(data))
# TODO: play with contrast and sharpening the images.
if image.width <= self.MIN_WIDTH:
return
if image.height <= self.MIN_HEIGHT:
return
if mode != self.api.GetPageSegMode():
self.api.SetPageSegMode(mode)
self.api.SetImage(image)
text = self.api.GetUTF8Text()
confidence = self.api.MeanTextConf()
log.info("%s chars (w: %s, h: %s, langs: %s, confidence: %s)",
len(text), image.width, image.height, languages,
confidence)
return text
except Exception as ex:
log.exception("Failed to OCR: %s", languages)
finally:
self.api.Clear()
class OCR(object):
MAX_MODELS = 5
DEFAULT_MODE = PSM.AUTO_OSD
# DEFAULT_MODE = PSM.AUTO
def __init__(self):
# Tesseract language types:
_, self.supported = get_languages()
def language_list(self, languages):
models = [c for c in alpha3(languages) if c in self.supported]
if len(models) > self.MAX_MODELS:
log.warning("Too many models, limit: %s", self.MAX_MODELS)
models = models[:self.MAX_MODELS]
models.append('eng')
return '+'.join(sorted(set(models)))
def configure_engine(self, languages, mode):
# log.info("Configuring OCR engine (%s)", languages)
if not hasattr(self, 'api'):
self.api = PyTessBaseAPI(lang=languages, oem=OEM.LSTM_ONLY)
if languages != self.api.GetInitLanguagesAsString():
self.api.Init(lang=languages, oem=OEM.LSTM_ONLY)
if mode != self.api.GetPageSegMode():
self.api.SetPageSegMode(mode)
return self.api
def extract_text(self, data, languages=None, mode=DEFAULT_MODE):
"""Extract text from a binary string of data."""
languages = self.language_list(languages)
api = self.configure_engine(languages, mode)
try:
image = Image.open(BytesIO(data))
# TODO: play with contrast and sharpening the images.
start_time = time.time()
api.SetImage(image)
text = api.GetUTF8Text()
confidence = api.MeanTextConf()
end_time = time.time()
duration = end_time - start_time
log.info("%s chars (w: %s, h: %s, langs: %s, c: %s), took: %.5f",
len(text), image.width, image.height, languages,
confidence, duration)
return text
except Exception as ex:
log.exception("Failed to OCR: %s", languages)
finally:
api.Clear()