def rpred(network,
im,
bounds,
pad=16,
line_normalization=True,
bidi_reordering=True):
"""
Uses a RNN to recognize text
Args:
network (kraken.lib.lstm.SegRecognizer): A SegRecognizer object
im (PIL.Image): Image to extract text from
bounds (dict): A dictionary containing a 'boxes' entry with a list of
coordinates (x0, y0, x1, y1) of a text line in the image
and an entry 'text_direction' containing
'horizontal-lr/rl/vertical-lr/rl'.
pad (int): Extra blank padding to the left and right of text line
line_normalization (bool): Dewarp line using the line estimator
contained in the network. If no normalizer
is available one using the default
parameters is created. By aware that you may
have to scale lines manually to the target
line height if disabled.
bidi_reordering (bool): Reorder classes in the ocr_record according to
the Unicode bidirectional algorithm for correct
display.
Yields:
An ocr_record containing the recognized text, absolute character
positions, and confidence values for each character.
"""
lnorm = getattr(network, 'lnorm', CenterNormalizer())
for box, coords in extract_boxes(im, bounds):
# check if boxes are non-zero in any dimension
if sum(coords[::2]) == 0 or coords[3] - coords[1] == 0:
yield ocr_record('', [], [])
continue
raw_line = pil2array(box)
# check if line is non-zero
if np.amax(raw_line) == np.amin(raw_line):
yield ocr_record('', [], [])
continue
if line_normalization:
# fail gracefully and return no recognition result in case the
# input line can not be normalized.
try:
box = dewarp(lnorm, box)
except:
yield ocr_record('', [], [])
continue
line = pil2array(box)
line = lstm.prepare_line(line, pad)
pred = network.predictString(line)
# calculate recognized LSTM locations of characters
scale = len(raw_line.T) / (len(network.outputs) - 2 * pad)
result = lstm.translate_back_locations(network.outputs)
pos = []
conf = []
for _, start, end, c in result:
if bounds['text_direction'].startswith('horizontal'):
pos.append((coords[0] + int(
(start - pad) * scale), coords[1], coords[0] + int(
(end - pad / 2) * scale), coords[3]))
else:
pos.append((coords[0], coords[1] + int(
(start - pad) * scale), coords[2], coords[1] + int(
(end - pad / 2) * scale)))
conf.append(c)
if bidi_reordering:
yield bidi_record(ocr_record(pred, pos, conf))
else:
yield ocr_record(pred, pos, conf)
def rpred(network,
im,
bounds,
pad=16,
line_normalization=True,
bidi_reordering=True):
"""
Uses a RNN to recognize text
Args:
network (kraken.lib.lstm.SegRecognizer): A SegRecognizer object
im (PIL.Image): Image to extract text from
bounds (dict): A dictionary containing a 'boxes' entry with a list of
coordinates (x0, y0, x1, y1) of a text line in the image
and an entry 'text_direction' containing
'horizontal-lr/rl/vertical-lr/rl'.
pad (int): Extra blank padding to the left and right of text line
line_normalization (bool): Dewarp line using the line estimator
contained in the network. If no normalizer
is available one using the default
parameters is created. By aware that you may
have to scale lines manually to the target
line height if disabled.
bidi_reordering (bool): Reorder classes in the ocr_record according to
the Unicode bidirectional algorithm for correct
display.
Yields:
An ocr_record containing the recognized text, absolute character
positions, and confidence values for each character.
"""
im_str = get_im_str(im)
logger.info(u'Running recognizer on {} with {} lines'.format(
im_str, len(bounds['boxes'])))
logger.debug(u'Loading line normalizer')
lnorm = getattr(network, 'lnorm', CenterNormalizer())
if not is_bitonal(im):
logger.info(u'Image is grayscale. Adjusting normalizer parameters')
lnorm.range = 2
for box, coords in extract_boxes(im, bounds):
# check if boxes are non-zero in any dimension
if sum(coords[::2]) == 0 or coords[3] - coords[1] == 0:
logger.warning(
u'bbox {} with zero dimension. Emitting empty record.'.format(
coords))
yield ocr_record('', [], [])
continue
raw_line = pil2array(box)
# check if line is non-zero
if np.amax(raw_line) == np.amin(raw_line):
logger.warning(
u'Empty line {}. Emitting empty record.'.format(coords))
yield ocr_record('', [], [])
continue
if line_normalization:
# fail gracefully and return no recognition result in case the
# input line can not be normalized.
try:
box = dewarp(lnorm, box)
except:
logger.warning(
u'Dewarping for bbox {} failed. Emitting empty record.'.
format(coords))
yield ocr_record('', [], [])
continue
line = pil2array(box)
logger.debug(u'Preparing line.')
line = lstm.prepare_line(line, pad)
logger.debug(u'Performing forward pass.')
pred = network.predictString(line)
logger.info(u'Prediction: {}'.format(pred))
# calculate recognized LSTM locations of characters
scale = len(raw_line.T) / (len(network.outputs) - 2 * pad)
logger.debug(u'Extracting labels.')
result = lstm.translate_back_locations(network.outputs)
pos = []
conf = []
for _, start, end, c in result:
if bounds['text_direction'].startswith('horizontal'):
xmin = coords[0] + int(max((start - pad) * scale, 0))
xmax = coords[0] + max(
int(min((end - pad) * scale, coords[2] - coords[0])), 1)
pos.append((xmin, coords[1], xmax, coords[3]))
else:
ymin = coords[1] + int(max((start - pad) * scale, 0))
ymax = coords[1] + max(
int(min((end - pad) * scale, coords[3] - coords[1])), 1)
pos.append((coords[0], ymin, coords[2], ymax))
conf.append(c)
if bidi_reordering:
logger.debug(u'BiDi reordering record.')
yield bidi_record(ocr_record(pred, pos, conf))
else:
yield ocr_record(pred, pos, conf)
def mm_rpred(nets,
im,
bounds,
pad=16,
line_normalization=True,
bidi_reordering=True):
"""
Multi-model version of kraken.rpred.rpred.
Takes a dictionary of ISO15924 script identifiers->models and an
script-annotated segmentation to dynamically select appropriate models for
these lines.
Args:
nets (dict): A dict mapping ISO15924 identifiers to SegRecognizer
objects. Recommended to be an defaultdict.
im (PIL.Image): Image to extract text from
bounds (dict): A dictionary containing a 'boxes' entry
with a list of lists of coordinates (script, (x0, y0,
x1, y1)) of a text line in the image and an entry
'text_direction' containing
'horizontal-lr/rl/vertical-lr/rl'.
pad (int): Extra blank padding to the left and right of text line
line_normalization (bool): Dewarp line using the line estimator
contained in the network. If no normalizer
is available one using the default
parameters is created. By aware that you may
have to scale lines manually to the target
line height if disabled.
bidi_reordering (bool): Reorder classes in the ocr_record according to
the Unicode bidirectional algorithm for correct
display.
Yields:
An ocr_record containing the recognized text, absolute character
positions, and confidence values for each character.
"""
for line in bounds['boxes']:
rec = ocr_record('', [], [])
for script, (box, coords) in zip(
map(lambda x: x[0], line),
extract_boxes(
im, {
'text_direction': bounds['text_direction'],
'boxes': map(lambda x: x[1], line)
})):
# check if boxes are non-zero in any dimension
if sum(coords[::2]) == 0 or coords[3] - coords[1] == 0:
continue
raw_line = pil2array(box)
# check if line is non-zero
if np.amax(raw_line) == np.amin(raw_line):
continue
if line_normalization:
# fail gracefully and return no recognition result in case the
# input line can not be normalized.
try:
lnorm = getattr(nets[script], 'lnorm', CenterNormalizer())
box = dewarp(lnorm, box)
except Exception as e:
continue
line = pil2array(box)
line = lstm.prepare_line(line, pad)
pred = nets[script].predictString(line)
# calculate recognized LSTM locations of characters
scale = len(raw_line.T) / (len(nets[script].outputs) - 2 * pad)
result = lstm.translate_back_locations(nets[script].outputs)
pos = []
conf = []
for _, start, end, c in result:
if bounds['text_direction'].startswith('horizontal'):
pos.append((coords[0] + int(
(start - pad) * scale), coords[1], coords[0] + int(
(end - pad / 2) * scale), coords[3]))
else:
pos.append((coords[0], coords[1] + int(
(start - pad) * scale), coords[2], coords[1] + int(
(end - pad / 2) * scale)))
conf.append(c)
rec.prediction += pred
rec.cuts.extend(pos)
rec.confidences.extend(conf)
if bidi_reordering:
yield bidi_record(rec)
else:
yield rec
def rpred(network, im, bounds, pad=16, line_normalization=True, bidi_reordering=True):
"""
Uses a RNN to recognize text
Args:
network (kraken.lib.lstm.SegRecognizer): A SegRecognizer object
im (PIL.Image): Image to extract text from
bounds (iterable): An iterable returning a tuple defining the absolute
coordinates (x0, y0, x1, y1) of a text line in the
Image.
pad (int): Extra blank padding to the left and right of text line
line_normalization (bool): Dewarp line using the line estimator
contained in the network. If no normalizer
is available one using the default
parameters is created. By aware that you may
have to scale lines manually to the target
line height if disabled.
bidi_reordering (bool): Reorder classes in the ocr_record according to
the Unicode bidirectional algorithm for correct
display.
Yields:
An ocr_record containing the recognized text, absolute character
positions, and confidence values for each character.
"""
lnorm = getattr(network, 'lnorm', CenterNormalizer())
for box, coords in extract_boxes(im, bounds):
# check if boxes are non-zero in any dimension
if sum(coords[::2]) == False or coords[3] - coords[1] == False:
yield ocr_record('', [], [])
continue
raw_line = pil2array(box)
# check if line is non-zero
if np.amax(raw_line) == np.amin(raw_line):
yield ocr_record('', [], [])
continue
if line_normalization:
# fail gracefully and return no recognition result in case the
# input line can not be normalized.
try:
box = dewarp(lnorm, box)
except:
yield ocr_record('', [], [])
continue
line = pil2array(box)
line = lstm.prepare_line(line, pad)
pred = network.predictString(line)
# calculate recognized LSTM locations of characters
scale = len(raw_line.T)/(len(network.outputs)-2 * pad)
result = lstm.translate_back_locations(network.outputs)
pos = []
conf = []
for _, start, end, c in result:
pos.append((coords[0] + int((start-pad)*scale), coords[1], coords[0] + int((end-pad/2)*scale), coords[3]))
conf.append(c)
if bidi_reordering:
yield bidi_record(ocr_record(pred, pos, conf))
else:
yield ocr_record(pred, pos, conf)