def vec_lines(heatmap: torch.Tensor,
cls_map: Dict,
scale: float,
text_direction: str = 'horizontal-lr',
reading_order_fn: Callable = polygonal_reading_order,
regions: Dict = None,
scal_im = None,
**kwargs):
"""
Computes lines from a stack of heatmaps, a class mapping, and scaling
factor.
"""
st_sep = cls_map['aux']['_start_separator']
end_sep = cls_map['aux']['_end_separator']
logger.info('Vectorizing baselines')
baselines = []
for bl_type, idx in cls_map['baselines'].items():
logger.debug(f'Vectorizing lines of type {bl_type}')
baselines.extend([(bl_type,x) for x in vectorize_lines(heatmap[(st_sep, end_sep, idx), :, :])])
logger.debug('Polygonizing lines')
lines = list(filter(lambda x: x[2] is not None, zip([x[0] for x in baselines],
[x[1] for x in baselines],
calculate_polygonal_environment(scal_im, [x[1] for x in baselines]))))
logger.debug('Scaling vectorized lines')
sc = scale_polygonal_lines([x[1:] for x in lines], scale)
lines = list(zip([x[0] for x in lines], [x[0] for x in sc], [x[1] for x in sc]))
logger.debug('Reordering baselines')
lines = reading_order_fn(lines=lines, regions=regions, text_direction=text_direction[-2:])
return [{'script': bl_type, 'baseline': bl, 'boundary': pl} for bl_type, bl, pl in lines]
def vec_lines(heatmap: torch.Tensor,
cls_map: Dict,
scale: float,
text_direction: str = 'horizontal-lr',
reading_order_fn: Callable = polygonal_reading_order,
regions: Dict = None,
scal_im=None,
suppl_obj=None,
topline=False,
**kwargs):
"""
Computes lines from a stack of heatmaps, a class mapping, and scaling
factor.
"""
st_sep = cls_map['aux']['_start_separator']
end_sep = cls_map['aux']['_end_separator']
logger.info('Vectorizing baselines')
baselines = []
for bl_type, idx in cls_map['baselines'].items():
logger.debug(f'Vectorizing lines of type {bl_type}')
baselines.extend([(bl_type, x)
for x in vectorize_lines(heatmap[(st_sep, end_sep,
idx), :, :])])
logger.debug('Polygonizing lines')
im_feats = gaussian_filter(sobel(scal_im), 0.5)
lines = []
reg_pols = [geom.Polygon(x) for x in regions]
for bl_idx in range(len(baselines)):
bl = baselines[bl_idx]
mid_point = geom.LineString(bl[1]).interpolate(0.5, normalized=True)
suppl_obj = [x[1] for x in baselines[:bl_idx] + baselines[bl_idx + 1:]]
for reg_idx, reg_pol in enumerate(reg_pols):
if reg_pol.contains(mid_point):
suppl_obj.append(regions[reg_idx])
pol = calculate_polygonal_environment(baselines=[bl[1]],
im_feats=im_feats,
suppl_obj=suppl_obj,
topline=topline)
if pol[0] is not None:
lines.append((bl[0], bl[1], pol[0]))
logger.debug('Scaling vectorized lines')
sc = scale_polygonal_lines([x[1:] for x in lines], scale)
lines = list(
zip([x[0] for x in lines], [x[0] for x in sc], [x[1] for x in sc]))
logger.debug('Reordering baselines')
lines = reading_order_fn(lines=lines,
regions=regions,
text_direction=text_direction[-2:])
return [{
'script': bl_type,
'baseline': bl,
'boundary': pl
} for bl_type, bl, pl in lines]
def segment(im,
text_direction: str = 'horizontal-lr',
mask: Optional[np.array] = None,
reading_order_fn: Callable = polygonal_reading_order,
model=None,
device: str = 'cpu'):
"""
Segments a page into text lines using the baseline segmenter.
Segments a page into text lines and returns the polyline formed by each
baseline and their estimated environment.
Args:
im (PIL.Image): An RGB image.
text_direction (str): Ignored by the segmenter but kept for
serialization.
mask (PIL.Image): A bi-level mask image of the same size as `im` where
0-valued regions are ignored for segmentation
purposes. Disables column detection.
reading_order_fn (function): Function to determine the reading order.
Has to accept a list of tuples (baselines,
polygon) and a text direction (`lr` or
`rl`).
model (vgsl.TorchVGSLModel): A TorchVGSLModel containing a segmentation
model. If none is given a default model
will be loaded.
device (str or torch.Device): The target device to run the neural
network on.
Returns:
{'text_direction': '$dir',
'type': 'baseline',
'lines': [
{'baseline': [[x0, y0], [x1, y1], ..., [x_n, y_n]], 'boundary': [[x0, y0, x1, y1], ... [x_m, y_m]]},
{'baseline': [[x0, ...]], 'boundary': [[x0, ...]]}
]
'regions': [
{'region': [[x0, y0], [x1, y1], ..., [x_n, y_n]], 'type': 'image'},
{'region': [[x0, ...]], 'type': 'text'}
]
}: A dictionary containing the text direction and under the key 'lines'
a list of reading order sorted baselines (polylines) and their
respective polygonal boundaries. The last and first point of each
boundary polygon is connected.
Raises:
KrakenInputException if the input image is not binarized or the text
direction is invalid.
"""
im_str = get_im_str(im)
logger.info(f'Segmenting {im_str}')
if model is None:
logger.info('No segmentation model given. Loading default model.')
model = vgsl.TorchVGSLModel.load_model(pkg_resources.resource_filename(__name__, 'blla.mlmodel'))
if model.one_channel_mode == '1' and not is_bitonal(im):
logger.warning('Running binary model on non-binary input image '
'(mode {}). This will result in severely degraded '
'performance'.format(im.mode))
model.eval()
model.to(device)
if mask:
if mask.mode != '1' and not is_bitonal(mask):
logger.error('Mask is not bitonal')
raise KrakenInputException('Mask is not bitonal')
mask = mask.convert('1')
if mask.size != im.size:
logger.error('Mask size {mask.size} doesn\'t match image size {im.size}')
raise KrakenInputException('Mask size {mask.size} doesn\'t match image size {im.size}')
logger.info('Masking enabled in segmenter.')
mask = pil2array(mask)
batch, channels, height, width = model.input
transforms = dataset.generate_input_transforms(batch, height, width, channels, 0, valid_norm=False)
res_tf = tf.Compose(transforms.transforms[:3])
scal_im = res_tf(im).convert('L')
with torch.no_grad():
logger.debug('Running network forward pass')
o = model.nn(transforms(im).unsqueeze(0).to(device))
logger.debug('Upsampling network output')
o = F.interpolate(o, size=scal_im.size[::-1])
o = o.squeeze().cpu().numpy()
scale = np.divide(im.size, o.shape[:0:-1])
# postprocessing
cls_map = model.user_metadata['class_mapping']
st_sep = cls_map['aux']['_start_separator']
end_sep = cls_map['aux']['_end_separator']
logger.info('Vectorizing baselines')
baselines = []
regions = {}
for bl_type, idx in cls_map['baselines'].items():
logger.debug(f'Vectorizing lines of type {bl_type}')
baselines.extend([(bl_type,x) for x in vectorize_lines(o[(st_sep, end_sep, idx), :, :])])
logger.info('Vectorizing regions')
for region_type, idx in cls_map['regions'].items():
logger.debug(f'Vectorizing lines of type {bl_type}')
regions[region_type] = vectorize_regions(o[idx])
logger.debug('Polygonizing lines')
lines = list(filter(lambda x: x[2] is not None, zip([x[0] for x in baselines],
[x[1] for x in baselines],
calculate_polygonal_environment(scal_im, [x[1] for x in baselines]))))
logger.debug('Scaling vectorized lines')
sc = scale_polygonal_lines([x[1:] for x in lines], scale)
lines = list(zip([x[0] for x in lines], [x[0] for x in sc], [x[1] for x in sc]))
logger.debug('Scaling vectorized regions')
for reg_id, regs in regions.items():
regions[reg_id] = scale_regions(regs, scale)
logger.debug('Reordering baselines')
order_regs = []
for regs in regions.values():
order_regs.extend(regs)
lines = reading_order_fn(lines=lines, regions=order_regs, text_direction=text_direction[-2:])
if 'class_mapping' in model.user_metadata and len(model.user_metadata['class_mapping']['baselines']) > 1:
script_detection = True
else:
script_detection = False
return {'text_direction': text_direction,
'type': 'baselines',
'lines': [{'script': bl_type, 'baseline': bl, 'boundary': pl} for bl_type, bl, pl in lines],
'regions': regions,
'script_detection': script_detection}
def vec_lines(heatmap: torch.Tensor,
cls_map: Dict[str, Dict[str, int]],
scale: float,
text_direction: str = 'horizontal-lr',
reading_order_fn: Callable = polygonal_reading_order,
regions: List[np.ndarray] = None,
scal_im: np.ndarray = None,
suppl_obj: List[np.ndarray] = None,
topline: Optional[bool] = False,
**kwargs) -> List[Dict[str, Any]]:
r"""
Computes lines from a stack of heatmaps, a class mapping, and scaling
factor.
Args:
heatmap: A stack of heatmaps of shape `NxHxW` output from the network.
cls_map: Dictionary mapping string identifiers to indices on the stack
of heatmaps.
scale: Scaling factor between heatmap and unscaled input image.
text_direction: Text directions used as hints in the reading order
algorithm.
reading_order_fn: Reading order calculation function.
regions: Regions to be used as boundaries during polygonization and
atomic blocks during reading order determination for lines
contained within.
scal_im: A numpy array containing the scaled input image.
suppl_obj: Supplementary objects which are used as boundaries during
polygonization.
topline: True for a topline, False for baseline, or None for a
centerline.
Returns:
A list of dictionaries containing the baselines, bounding polygons, and
line type in reading order:
.. code-block::
:force:
[{'script': '$baseline_type', baseline': [[x0, y0], [x1, y1], ..., [x_n, y_n]], 'boundary': [[x0, y0, x1, y1], ... [x_m, y_m]]},
{'script': '$baseline_type', baseline': [[x0, ...]], 'boundary': [[x0, ...]]},
{'script': '$baseline_type', baseline': [[x0, ...]], 'boundary': [[x0, ...]]},
...
]
"""
st_sep = cls_map['aux']['_start_separator']
end_sep = cls_map['aux']['_end_separator']
logger.info('Vectorizing baselines')
baselines = []
for bl_type, idx in cls_map['baselines'].items():
logger.debug(f'Vectorizing lines of type {bl_type}')
baselines.extend([(bl_type, x)
for x in vectorize_lines(heatmap[(st_sep, end_sep,
idx), :, :])])
logger.debug('Polygonizing lines')
im_feats = gaussian_filter(sobel(scal_im), 0.5)
lines = []
reg_pols = [geom.Polygon(x) for x in regions]
for bl_idx in range(len(baselines)):
bl = baselines[bl_idx]
mid_point = geom.LineString(bl[1]).interpolate(0.5, normalized=True)
suppl_obj = [x[1] for x in baselines[:bl_idx] + baselines[bl_idx + 1:]]
for reg_idx, reg_pol in enumerate(reg_pols):
if reg_pol.contains(mid_point):
suppl_obj.append(regions[reg_idx])
pol = calculate_polygonal_environment(baselines=[bl[1]],
im_feats=im_feats,
suppl_obj=suppl_obj,
topline=topline)
if pol[0] is not None:
lines.append((bl[0], bl[1], pol[0]))
logger.debug('Scaling vectorized lines')
sc = scale_polygonal_lines([x[1:] for x in lines], scale)
lines = list(
zip([x[0] for x in lines], [x[0] for x in sc], [x[1] for x in sc]))
logger.debug('Reordering baselines')
lines = reading_order_fn(lines=lines,
regions=regions,
text_direction=text_direction[-2:])
return [{
'tags': {
'type': bl_type
},
'baseline': bl,
'boundary': pl
} for bl_type, bl, pl in lines]
