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464 lines
12 KiB
464 lines
12 KiB
#!/usr/bin/env python
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"""
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Python-tesseract. For more information: https://github.com/madmaze/pytesseract
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"""
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import os
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import shlex
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import string
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import subprocess
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import sys
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import tempfile
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from contextlib import contextmanager
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from csv import QUOTE_NONE
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from distutils.version import LooseVersion
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from functools import wraps
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from glob import iglob
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from io import BytesIO
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from os.path import normcase, normpath, realpath
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from pkgutil import find_loader
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from threading import Timer
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try:
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from PIL import Image
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except ImportError:
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import Image
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numpy_installed = find_loader('numpy') is not None
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if numpy_installed:
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from numpy import ndarray
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pandas_installed = find_loader('pandas') is not None
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if pandas_installed:
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import pandas as pd
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# CHANGE THIS IF TESSERACT IS NOT IN YOUR PATH, OR IS NAMED DIFFERENTLY
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tesseract_cmd = 'tesseract'
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RGB_MODE = 'RGB'
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SUPPORTED_FORMATS = {
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'JPEG', 'PNG', 'PBM', 'PGM', 'PPM', 'TIFF', 'BMP', 'GIF'
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}
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OSD_KEYS = {
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'Page number': ('page_num', int),
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'Orientation in degrees': ('orientation', int),
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'Rotate': ('rotate', int),
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'Orientation confidence': ('orientation_conf', float),
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'Script': ('script', str),
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'Script confidence': ('script_conf', float)
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}
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class Output:
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BYTES = 'bytes'
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DATAFRAME = 'data.frame'
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DICT = 'dict'
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STRING = 'string'
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class PandasNotSupported(EnvironmentError):
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def __init__(self):
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super(PandasNotSupported, self).__init__('Missing pandas package')
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class TesseractError(RuntimeError):
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def __init__(self, status, message):
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self.status = status
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self.message = message
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self.args = (status, message)
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class TesseractNotFoundError(EnvironmentError):
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def __init__(self):
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super(TesseractNotFoundError, self).__init__(
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tesseract_cmd + " is not installed or it's not in your path"
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)
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class TSVNotSupported(EnvironmentError):
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def __init__(self):
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super(TSVNotSupported, self).__init__(
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'TSV output not supported. Tesseract >= 3.05 required'
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)
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def kill(process, code):
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process.kill()
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process.returncode = code
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@contextmanager
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def timeout_manager(proc, seconds=0):
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try:
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if not seconds:
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yield proc.communicate()[1]
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return
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timeout_code = -1
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timer = Timer(seconds, kill, [proc, timeout_code])
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timer.start()
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try:
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_, error_string = proc.communicate()
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yield error_string
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finally:
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timer.cancel()
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if proc.returncode is timeout_code and not error_string:
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raise RuntimeError('Tesseract process timeout')
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finally:
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proc.stdin.close()
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proc.stdout.close()
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proc.stderr.close()
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def run_once(func):
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@wraps(func)
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def wrapper(*args, **kwargs):
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if wrapper._result is wrapper:
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wrapper._result = func(*args, **kwargs)
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return wrapper._result
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wrapper._result = wrapper
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return wrapper
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def get_errors(error_string):
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return u' '.join(
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line for line in error_string.decode('utf-8').splitlines()
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).strip()
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def cleanup(temp_name):
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""" Tries to remove temp files by filename wildcard path. """
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for filename in iglob(temp_name + '*' if temp_name else temp_name):
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try:
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os.remove(filename)
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except OSError:
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pass
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def prepare(image):
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if numpy_installed and isinstance(image, ndarray):
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image = Image.fromarray(image)
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if not isinstance(image, Image.Image):
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raise TypeError('Unsupported image object')
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extension = 'PNG' if not image.format else image.format
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if extension not in SUPPORTED_FORMATS:
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raise TypeError('Unsupported image format/type')
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if not image.mode.startswith(RGB_MODE):
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image = image.convert(RGB_MODE)
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if 'A' in image.getbands():
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# discard and replace the alpha channel with white background
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background = Image.new(RGB_MODE, image.size, (255, 255, 255))
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background.paste(image, (0, 0), image)
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image = background
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image.format = extension
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return image, extension
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def save_image(image):
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with tempfile.NamedTemporaryFile(prefix='tess_', delete=False) as f:
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temp_name = f.name
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if isinstance(image, str):
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return temp_name, realpath(normpath(normcase(image)))
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image, extension = prepare(image)
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input_file_name = temp_name + os.extsep + extension
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image.save(input_file_name, format=extension, **image.info)
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return temp_name, input_file_name
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def subprocess_args(include_stdout=True):
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# See https://github.com/pyinstaller/pyinstaller/wiki/Recipe-subprocess
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# for reference and comments.
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kwargs = {
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'stdin': subprocess.PIPE,
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'stderr': subprocess.PIPE,
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'startupinfo': None,
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'env': os.environ
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}
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if hasattr(subprocess, 'STARTUPINFO'):
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kwargs['startupinfo'] = subprocess.STARTUPINFO()
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kwargs['startupinfo'].dwFlags |= subprocess.STARTF_USESHOWWINDOW
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kwargs['startupinfo'].wShowWindow = subprocess.SW_HIDE
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if include_stdout:
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kwargs['stdout'] = subprocess.PIPE
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return kwargs
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def run_tesseract(input_filename,
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output_filename_base,
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extension,
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lang,
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config='',
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nice=0,
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timeout=0):
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cmd_args = []
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if not sys.platform.startswith('win32') and nice != 0:
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cmd_args += ('nice', '-n', str(nice))
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cmd_args += (tesseract_cmd, input_filename, output_filename_base)
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if lang is not None:
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cmd_args += ('-l', lang)
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if config:
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cmd_args += shlex.split(config)
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if extension and extension not in {'box', 'osd', 'tsv'}:
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cmd_args.append(extension)
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try:
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proc = subprocess.Popen(cmd_args, **subprocess_args())
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except OSError:
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raise TesseractNotFoundError()
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with timeout_manager(proc, timeout) as error_string:
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if proc.returncode:
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raise TesseractError(proc.returncode, get_errors(error_string))
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def run_and_get_output(image,
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extension='',
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lang=None,
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config='',
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nice=0,
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timeout=0,
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return_bytes=False):
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temp_name, input_filename = '', ''
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try:
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temp_name, input_filename = save_image(image)
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kwargs = {
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'input_filename': input_filename,
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'output_filename_base': temp_name + '_out',
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'extension': extension,
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'lang': lang,
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'config': config,
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'nice': nice,
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'timeout': timeout
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}
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run_tesseract(**kwargs)
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filename = kwargs['output_filename_base'] + os.extsep + extension
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with open(filename, 'rb') as output_file:
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if return_bytes:
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return output_file.read()
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return output_file.read().decode('utf-8').strip()
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finally:
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cleanup(temp_name)
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def file_to_dict(tsv, cell_delimiter, str_col_idx):
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result = {}
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rows = [row.split(cell_delimiter) for row in tsv.split('\n')]
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if not rows:
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return result
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header = rows.pop(0)
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length = len(header)
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if len(rows[-1]) < length:
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# Fixes bug that occurs when last text string in TSV is null, and
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# last row is missing a final cell in TSV file
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rows[-1].append('')
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if str_col_idx < 0:
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str_col_idx += length
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for i, head in enumerate(header):
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result[head] = list()
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for row in rows:
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if len(row) <= i:
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continue
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val = row[i]
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if row[i].isdigit() and i != str_col_idx:
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val = int(row[i])
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result[head].append(val)
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return result
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def is_valid(val, _type):
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if _type is int:
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return val.isdigit()
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if _type is float:
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try:
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float(val)
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return True
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except ValueError:
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return False
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return True
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def osd_to_dict(osd):
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return {
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OSD_KEYS[kv[0]][0]: OSD_KEYS[kv[0]][1](kv[1]) for kv in (
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line.split(': ') for line in osd.split('\n')
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) if len(kv) == 2 and is_valid(kv[1], OSD_KEYS[kv[0]][1])
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}
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@run_once
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def get_tesseract_version():
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"""
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Returns LooseVersion object of the Tesseract version
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"""
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try:
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return LooseVersion(
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subprocess.check_output(
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[tesseract_cmd, '--version'], stderr=subprocess.STDOUT
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).decode('utf-8').split()[1].lstrip(string.printable[10:])
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)
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except OSError:
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raise TesseractNotFoundError()
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def image_to_string(image,
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lang=None,
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config='',
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nice=0,
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output_type=Output.STRING,
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timeout=0):
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"""
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Returns the result of a Tesseract OCR run on the provided image to string
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"""
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args = [image, 'txt', lang, config, nice, timeout]
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return {
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Output.BYTES: lambda: run_and_get_output(*(args + [True])),
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Output.DICT: lambda: {'text': run_and_get_output(*args)},
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Output.STRING: lambda: run_and_get_output(*args),
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}[output_type]()
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def image_to_pdf_or_hocr(image,
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lang=None,
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config='',
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nice=0,
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extension='pdf',
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timeout=0):
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"""
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Returns the result of a Tesseract OCR run on the provided image to pdf/hocr
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"""
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if extension not in {'pdf', 'hocr'}:
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raise ValueError('Unsupported extension: {}'.format(extension))
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args = [image, extension, lang, config, nice, timeout, True]
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return run_and_get_output(*args)
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def image_to_boxes(image,
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lang=None,
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config='',
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nice=0,
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output_type=Output.STRING,
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timeout=0):
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"""
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Returns string containing recognized characters and their box boundaries
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"""
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config += ' batch.nochop makebox'
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args = [image, 'box', lang, config, nice, timeout]
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return {
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Output.BYTES: lambda: run_and_get_output(*(args + [True])),
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Output.DICT: lambda: file_to_dict(
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'char left bottom right top page\n' + run_and_get_output(*args),
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' ',
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0),
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Output.STRING: lambda: run_and_get_output(*args),
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}[output_type]()
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def get_pandas_output(args):
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if not pandas_installed:
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raise PandasNotSupported()
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return pd.read_csv(
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BytesIO(run_and_get_output(*args)),
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quoting=QUOTE_NONE,
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sep='\t'
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)
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def image_to_data(image,
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lang=None,
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config='',
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nice=0,
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output_type=Output.STRING,
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timeout=0):
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"""
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Returns string containing box boundaries, confidences,
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and other information. Requires Tesseract 3.05+
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"""
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if get_tesseract_version() < '3.05':
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raise TSVNotSupported()
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config = '{} {}'.format('-c tessedit_create_tsv=1', config.strip()).strip()
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args = [image, 'tsv', lang, config, nice, timeout]
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return {
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Output.BYTES: lambda: run_and_get_output(*(args + [True])),
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Output.DATAFRAME: lambda: get_pandas_output(args + [True]),
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Output.DICT: lambda: file_to_dict(run_and_get_output(*args), '\t', -1),
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Output.STRING: lambda: run_and_get_output(*args),
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}[output_type]()
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def image_to_osd(image,
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lang='osd',
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config='',
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nice=0,
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output_type=Output.STRING,
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timeout=0):
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"""
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Returns string containing the orientation and script detection (OSD)
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"""
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config = '{}-psm 0 {}'.format(
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'' if get_tesseract_version() < '3.05' else '-',
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config.strip()
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).strip()
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args = [image, 'osd', lang, config, nice, timeout]
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return {
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Output.BYTES: lambda: run_and_get_output(*(args + [True])),
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Output.DICT: lambda: osd_to_dict(run_and_get_output(*args)),
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Output.STRING: lambda: run_and_get_output(*args),
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}[output_type]()
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def main():
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if len(sys.argv) == 2:
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filename, lang = sys.argv[1], None
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elif len(sys.argv) == 4 and sys.argv[1] == '-l':
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filename, lang = sys.argv[3], sys.argv[2]
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else:
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sys.stderr.write('Usage: python pytesseract.py [-l lang] input_file\n')
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exit(2)
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try:
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with Image.open(filename) as img:
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print(image_to_string(img, lang=lang))
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except IOError:
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sys.stderr.write('ERROR: Could not open file "%s"\n' % filename)
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exit(1)
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if __name__ == '__main__':
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main()
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