def segmentation_kraken(doc, method=u'segment_kraken', black_colseps=False):
"""
Performs page segmentation using kraken's built-in algorithm and writes a
skeleton TEI file.
Args:
doc (unicode, unicode): The input document tuple
method (unicode): The suffix string append to all output files
black_colseps (bool): Assume black column separator instead of white
ones.
Returns:
Two storage tuples with the first one containing the segmentation and
the second one being the file the segmentation was calculated upon.
"""
input_path = storage.get_abs_path(*doc)
output_path, ext = os.path.splitext(
storage.insert_suffix(input_path, method))
logger.debug('Reading image using PIL')
img = Image.open(input_path)
with open(output_path + '.xml', 'w') as fp:
logger.debug('Initializing TEI with {} ({} {})'.format(
doc[1], *img.size))
tei = OCRRecord()
tei.img = storage.get_url(*doc)
tei.dimensions = img.size
tei.title = os.path.basename(doc[1])
tei.add_respstmt('kraken', 'page segmentation')
for seg in pageseg.segment(img, black_colseps=black_colseps)['boxes']:
logger.debug('Found line at {} {} {} {}'.format(*seg))
tei.add_line(seg)
logger.debug('Write segmentation to {}'.format(fp.name))
tei.write_tei(fp)
return storage.get_storage_path(output_path + '.xml')
def segmentation_kraken(doc, method=u'segment_kraken', black_colseps=False):
"""
Performs page segmentation using kraken's built-in algorithm and writes a
skeleton TEI file.
Args:
doc (unicode, unicode): The input document tuple
method (unicode): The suffix string append to all output files
black_colseps (bool): Assume black column separator instead of white
ones.
Returns:
Two storage tuples with the first one containing the segmentation and
the second one being the file the segmentation was calculated upon.
"""
input_path = storage.get_abs_path(*doc)
output_path, ext = os.path.splitext(storage.insert_suffix(input_path,
method))
logger.debug('Reading image using PIL')
img = Image.open(input_path)
with open(output_path + '.xml', 'w') as fp:
logger.debug('Initializing TEI with {} ({} {})'.format(doc[1], *img.size))
tei = OCRRecord()
tei.img = storage.get_url(*doc)
tei.dimensions = img.size
tei.title = os.path.basename(doc[1])
tei.add_respstmt('kraken', 'page segmentation')
for seg in pageseg.segment(img, black_colseps=black_colseps)['boxes']:
logger.debug('Found line at {} {} {} {}'.format(*seg))
tei.add_line(seg)
logger.debug('Write segmentation to {}'.format(fp.name))
tei.write_tei(fp)
return storage.get_storage_path(output_path + '.xml')
def segmentation_tesseract(doc, method=u'segment_tesseract'):
"""
Performs page segmentation using tesseract's built-in algorithm and writes
a TEI XML segmentation file.
Args:
doc (unicode, unicode): The input document tuple
method (unicode): The suffix string appended to all output files.
Returns:
Two storage tuples with the first one containing the segmentation and
the second one being the file the segmentation was calculated upon.
"""
input_path = storage.get_abs_path(*doc)
output_path = splitext(storage.insert_suffix(input_path,
method))[0] + '.xml'
ver = tesseract.TessVersion()
if int(ver.split('.')[0]) < 3 or int(ver.split('.')[1]) < 2:
raise NidabaTesseractException('libtesseract version is too old. Set '
'implementation to direct.')
# tesseract has a tendency to crash arbitrarily on some inputs
# necessitating execution in a separate process to ensure the worker
# doesn't just die. We use fork as the multiprocessing module thinks
# programmers are too stupid to reap their children.
logger.info('Forking before entering unstable ctypes code')
pid = os.fork()
if pid != 0:
try:
logger.info('Waiting for child to complete')
_, status = os.waitpid(pid, 0)
except OSError as e:
if e.errno not in (errno.EINTR, errno.ECHILD):
raise
return storage.get_storage_path(output_path)
if os.WIFSIGNALED(status):
raise NidabaTesseractException(
'Tesseract killed by signal: {0}'.format(os.WTERMSIG(status)))
return storage.get_storage_path(output_path)
api = tesseract.TessBaseAPICreate()
rc = tesseract.TessBaseAPIInit3(api, tessdata.encode('utf-8'), None)
if (rc):
tesseract.TessBaseAPIDelete(api)
raise NidabaTesseractException('Tesseract initialization failed.')
# only do segmentation and script detection
logger.debug('Setting page set mode to 2')
tesseract.TessBaseAPISetPageSegMode(api, 2)
logger.debug('Reading {} using leptonica'.format(input_path))
pix = leptonica.pixRead(input_path.encode('utf-8'))
logger.debug('Setting PIX as input image')
tesseract.TessBaseAPISetImage2(api, pix)
logger.debug('Analyzing page layout')
it = tesseract.TessBaseAPIAnalyseLayout(api)
logger.debug('Destroying PIX')
leptonica.pixDestroy(ctypes.byref(pix))
x0, y0, x1, y1 = (ctypes.c_int(), ctypes.c_int(), ctypes.c_int(),
ctypes.c_int())
w, h = Image.open(input_path).size
logger.info('Initializing TEI XML file with {}x{} {}/{}'.format(
w, h, *doc))
tei = OCRRecord()
tei.dimensions = (w, h)
tei.img = storage.get_url(*doc)
tei.title = os.path.basename(doc[1])
tei.add_respstmt('tesseract', 'page segmentation')
while True:
if tesseract.TessPageIteratorIsAtBeginningOf(it, RIL_TEXTLINE):
tesseract.TessPageIteratorBoundingBox(it, RIL_TEXTLINE,
ctypes.byref(x0),
ctypes.byref(y0),
ctypes.byref(x1),
ctypes.byref(y1))
tei.add_line((x0.value, y0.value, x1.value, y1.value))
logger.debug('Segmenter found new line at {} {} {} {}'.format(
x0.value, y0.value, x1.value, y1.value))
if tesseract.TessPageIteratorIsAtBeginningOf(it, RIL_WORD):
tesseract.TessPageIteratorBoundingBox(it, RIL_WORD,
ctypes.byref(x0),
ctypes.byref(y0),
ctypes.byref(x1),
ctypes.byref(y1))
tei.add_segment((x0.value, y0.value, x1.value, y1.value))
logger.debug('Segmenter found new word at {} {} {} {}'.format(
x0.value, y0.value, x1.value, y1.value))
tesseract.TessPageIteratorBoundingBox(it, RIL_SYMBOL, ctypes.byref(x0),
ctypes.byref(y0),
ctypes.byref(x1),
ctypes.byref(y1))
tei.add_graphemes([{
'grapheme': '',
'bbox': (x0.value, y0.value, x1.value, y1.value)
}])
logger.debug('Segmenter found new symbol at {} {} {} {}'.format(
x0.value, y0.value, x1.value, y1.value))
if not tesseract.TessPageIteratorNext(it, RIL_SYMBOL):
logger.debug('No more elements on page')
break
logger.debug('Deleting page iterator and base API')
tesseract.TessPageIteratorDelete(it)
tesseract.TessBaseAPIEnd(api)
tesseract.TessBaseAPIDelete(api)
logger.info('Writing segmentation to {}'.format(output_path))
with open(output_path, 'w') as fp:
tei.write_tei(fp)
logger.info('Quitting child process')
os._exit(os.EX_OK)
return storage.get_storage_path(output_path)
def segmentation_tesseract(doc, method=u'segment_tesseract'):
"""
Performs page segmentation using tesseract's built-in algorithm and writes
a TEI XML segmentation file.
Args:
doc (unicode, unicode): The input document tuple
method (unicode): The suffix string appended to all output files.
Returns:
Two storage tuples with the first one containing the segmentation and
the second one being the file the segmentation was calculated upon.
"""
input_path = storage.get_abs_path(*doc)
output_path = splitext(storage.insert_suffix(input_path, method))[0] + '.xml'
ver = tesseract.TessVersion()
if int(ver.split('.')[0]) < 3 or int(ver.split('.')[1]) < 2:
raise NidabaTesseractException('libtesseract version is too old. Set '
'implementation to direct.')
# tesseract has a tendency to crash arbitrarily on some inputs
# necessitating execution in a separate process to ensure the worker
# doesn't just die. We use fork as the multiprocessing module thinks
# programmers are too stupid to reap their children.
logger.info('Forking before entering unstable ctypes code')
pid = os.fork()
if pid != 0:
try:
logger.info('Waiting for child to complete')
_, status = os.waitpid(pid, 0)
except OSError as e:
if e.errno not in (errno.EINTR, errno.ECHILD):
raise
return storage.get_storage_path(output_path)
if os.WIFSIGNALED(status):
raise NidabaTesseractException('Tesseract killed by signal: {0}'.format(os.WTERMSIG(status)))
return storage.get_storage_path(output_path)
api = tesseract.TessBaseAPICreate()
rc = tesseract.TessBaseAPIInit3(api, tessdata.encode('utf-8'), None)
if (rc):
tesseract.TessBaseAPIDelete(api)
raise NidabaTesseractException('Tesseract initialization failed.')
# only do segmentation and script detection
logger.debug('Setting page set mode to 2')
tesseract.TessBaseAPISetPageSegMode(api, 2)
logger.debug('Reading {} using leptonica'.format(input_path))
pix = leptonica.pixRead(input_path.encode('utf-8'))
logger.debug('Setting PIX as input image')
tesseract.TessBaseAPISetImage2(api, pix)
logger.debug('Analyzing page layout')
it = tesseract.TessBaseAPIAnalyseLayout(api)
logger.debug('Destroying PIX')
leptonica.pixDestroy(ctypes.byref(pix))
x0, y0, x1, y1 = (ctypes.c_int(), ctypes.c_int(), ctypes.c_int(),
ctypes.c_int())
w, h = Image.open(input_path).size
logger.info('Initializing TEI XML file with {}x{} {}/{}'.format(w, h, *doc))
tei = OCRRecord()
tei.dimensions = (w, h)
tei.img = storage.get_url(*doc)
tei.title = os.path.basename(doc[1])
tei.add_respstmt('tesseract', 'page segmentation')
while True:
if tesseract.TessPageIteratorIsAtBeginningOf(it, RIL_TEXTLINE):
tesseract.TessPageIteratorBoundingBox(it,
RIL_TEXTLINE,
ctypes.byref(x0),
ctypes.byref(y0),
ctypes.byref(x1),
ctypes.byref(y1))
tei.add_line((x0.value, y0.value, x1.value, y1.value))
logger.debug('Segmenter found new line at {} {} {} {}'.format(x0.value,
y0.value,
x1.value,
y1.value))
if tesseract.TessPageIteratorIsAtBeginningOf(it, RIL_WORD):
tesseract.TessPageIteratorBoundingBox(it,
RIL_WORD,
ctypes.byref(x0),
ctypes.byref(y0),
ctypes.byref(x1),
ctypes.byref(y1))
tei.add_segment((x0.value, y0.value, x1.value, y1.value))
logger.debug('Segmenter found new word at {} {} {} {}'.format(x0.value,
y0.value,
x1.value,
y1.value))
tesseract.TessPageIteratorBoundingBox(it,
RIL_SYMBOL,
ctypes.byref(x0),
ctypes.byref(y0),
ctypes.byref(x1),
ctypes.byref(y1))
tei.add_graphemes([{'grapheme': '', 'bbox': (x0.value, y0.value, x1.value, y1.value)}])
logger.debug('Segmenter found new symbol at {} {} {} {}'.format(x0.value,
y0.value,
x1.value,
y1.value))
if not tesseract.TessPageIteratorNext(it, RIL_SYMBOL):
logger.debug('No more elements on page')
break
logger.debug('Deleting page iterator and base API')
tesseract.TessPageIteratorDelete(it)
tesseract.TessBaseAPIEnd(api)
tesseract.TessBaseAPIDelete(api)
logger.info('Writing segmentation to {}'.format(output_path))
with open(output_path, 'w') as fp:
tei.write_tei(fp)
logger.info('Quitting child process')
os._exit(os.EX_OK)
return storage.get_storage_path(output_path)