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#!/usr/bin/env python2.7
# Copyright 2013 Virantha Ekanayake All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Run Tesseract to generate hocr file
"""
import os, sys
import logging
import subprocess
import glob
from subprocess import CalledProcessError
from multiprocessing import Pool
from pypdfocr_interrupts import init_worker
def error(text):
print("ERROR: %s" % text)
sys.exit(-1)
# Ugly hack to pass in object method to the multiprocessing library
# From http://www.rueckstiess.net/research/snippets/show/ca1d7d90
# Basically gets passed in a pair of (self, arg), and calls the method
def unwrap_self(arg, **kwarg):
return PyTesseract.make_hocr_from_pnm(*arg, **kwarg)
class PyTesseract(object):
"""Class to wrap all the tesseract calls"""
def __init__(self, config):
"""
Detect windows tesseract location.
"""
self.lang = 'eng'
self.required = "3.02.02"
self.threads = config.get('threads',4)
if "binary" in config: # Override location of binary
binary = config['binary']
if os.name == 'nt':
binary = '"%s"' % binary
binary = binary.replace("\\", "\\\\")
logging.info("Setting location for tesseracdt executable to %s" % (binary))
else:
if str(os.name) == 'nt':
# Explicit str here to get around some MagicMock stuff for testing that I don't quite understand
binary = '"c:\\Program Files (x86)\\Tesseract-OCR\\tesseract.exe"'
else:
binary = "tesseract"
self.binary = binary
self.msgs = {
'TS_MISSING': """
Could not execute %s
Please make sure you have Tesseract installed correctly
""" % self.binary,
'TS_VERSION':'Tesseract version is too old',
'TS_img_MISSING':'Cannot find specified tiff file',
'TS_FAILED': 'Tesseract-OCR execution failed!',
}
def _is_version_uptodate(self):
"""
Make sure the version is current
"""
logging.info("Checking tesseract version")
cmd = '%s -v' % (self.binary)
logging.info(cmd)
try:
ret_output = subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
except CalledProcessError:
# Could not run tesseract
error(self.msgs['TS_MISSING'])
ver_str = '0.0.0'
for line in ret_output.splitlines():
if 'tesseract' in line:
ver_str = line.split(' ')[1]
if ver_str.endswith('dev'): # Fix for version strings that end in 'dev'
ver_str = ver_str[:-3]
# Iterate through the version dots
ver = [int(x) for x in ver_str.split('.')]
req = [int(x) for x in self.required.split('.')]
# Aargh, in windows 3.02.02 is reported as version 3.02
# SFKM
if str(os.name) == 'nt':
req = req[:2]
version_good = False
for i,num in enumerate(req):
if len(ver) < i+1:
# This minor version number is not present in tesseract, so it must be
# lower than required. (3.02 < 3.02.01)
break
if ver[i]==num and len(ver) == i+1 and len(ver)==len(req):
# 3.02.02 == 3.02.02
version_good = True
continue
if ver[i]>num:
# 4.0 > 3.02.02
# 3.03.02 > 3.02.02
version_good = True
break
if ver[i]<num:
# 3.01.02 < 3.02.02
break
return version_good, ver_str
def _warn(self, msg): # pragma: no cover
print("WARNING: %s" % msg)
def make_hocr_from_pnms(self, fns):
uptodate,ver = self._is_version_uptodate()
if not uptodate:
error(self.msgs['TS_VERSION']+ " (found %s, required %s)" % (ver, self.required))
# Glob it
#fns = glob.glob(img_filename)
logging.debug("Making pool for tesseract")
pool = Pool(processes=self.threads, initializer=init_worker)
try:
hocr_filenames = pool.map(unwrap_self, zip([self]*len(fns), fns))
pool.close()
except KeyboardInterrupt or Exception:
print("Caught keyboard interrupt... terminating")
pool.terminate()
raise
finally:
pool.join()
return zip(fns,hocr_filenames)
def make_hocr_from_pnm(self, img_filename):
basename,filext = os.path.splitext(img_filename)
hocr_filename = "%s.html" % basename
if not os.path.exists(img_filename):
error(self.msgs['TS_img_MISSING'] + " %s" % (img_filename))
logging.info("Running OCR on %s to create %s.html" % (img_filename, basename))
cmd = '%s "%s" "%s" -psm 1 -c hocr_font_info=1 -l %s hocr' % (self.binary, img_filename, basename, self.lang)
logging.info(cmd)
try:
ret_output = subprocess.check_output(cmd, shell=True, stderr=subprocess.STDOUT)
except subprocess.CalledProcessError as e:
# Could not run tesseract
print e.output
self._warn (self.msgs['TS_FAILED'])
if os.path.isfile(hocr_filename):
# Output format is html for old versions of tesseract
logging.info("Created %s.html" % basename)
return hocr_filename
else:
# Try changing extension to .hocr for tesseract 3.03 and higher
hocr_filename = "%s.hocr" % basename
if os.path.isfile(hocr_filename):
logging.info("Created %s.hocr" % basename)
return hocr_filename
else:
error(self.msgs['TS_FAILED'])
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