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dinglehopper
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🚧 dinglehopper: Hierarchical text representation

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pull/38/head
Gerber, Mike 4 years ago
parent db6292611f
commit 96b55f1806
2 changed files with 90 additions and 67 deletions
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117
qurator/dinglehopper/ocr_files.py
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@ -15,14 +15,52 @@ import unicodedata
import re
class Normalization(enum.Enum):
NFC = 1
NFC_MUFI = 2 # TODO
NFC_SBB = 3
@attr.s(frozen=True)
class ExtractedText:
segments = attr.ib(converter=list)
joiner = attr.ib(type=str)
# TODO Types are not validated (attr does not do this yet)
segment_id = attr.ib(type=Optional[str])
@segment_id.validator
def check(self, _, value):
if value is None:
return
if not re.match(r'[\w\d_-]+', value):
raise ValueError('Malformed segment id "{}"'.format(value))
# An object contains either
# a. _text itself
# b. or segments (ExtractedText) and a joiner
# TODO validator
segments = attr.ib(type=Optional[list], converter=attr.converters.optional(list))
joiner = attr.ib(type=Optional[str])
_text = attr.ib(type=Optional[str])
@segments.validator
def check(self, _, value):
if value is not None and self._text is not None:
raise ValueError("Can't have both segments and text")
@_text.validator
def check(self, _, value):
if value is not None and normalize(value, self.normalization) != value:
raise ValueError('String "{}" is not normalized.'.format(value))
normalization = attr.ib(converter=Normalization, default=Normalization.NFC_SBB)
@property
def text(self):
if self._text is not None:
if self._text == '':
return None
else:
return self._text
else:
return self.joiner.join(s.text for s in self.segments)
_segment_id_for_pos = None
@ -34,17 +72,30 @@ class ExtractedText:
for s in self.segments:
segment_id_for_pos.extend(repeat(s.segment_id, len(s.text)))
segment_id_for_pos.extend(repeat(None, len(self.joiner)))
segment_id_for_pos = segment_id_for_pos[:-len(self.joiner)]
# This is frozen, so we have to jump through the hoop:
object.__setattr__(self, '_segment_id_for_pos', segment_id_for_pos)
assert self._segment_id_for_pos
return self._segment_id_for_pos[pos]
@classmethod
def from_text_segment(cls, text_segment, nsmap):
"""Build an ExtractedText from a PAGE content text element"""
segment_id = text_segment.attrib['id']
segment_text = None
with suppress(AttributeError):
segment_text = text_segment.find('./page:TextEquiv/page:Unicode', namespaces=nsmap).text
segment_text = segment_text or ''
segment_text = normalize_sbb(segment_text) # FIXME hardcoded SBB normalization
segment_text = segment_text or ''
return cls(segment_id, None, None, segment_text)
@classmethod
def from_text(cls, text):
return cls(None, None, None, text)
class Normalization(enum.Enum):
NFC = 1
NFC_MUFI = 2 # TODO
NFC_SBB = 3
def normalize(text, normalization):
@ -63,37 +114,6 @@ def normalize_sbb(t):
return normalize(t, Normalization.NFC_SBB)
@attr.s(frozen=True)
class ExtractedTextSegment:
segment_id = attr.ib(type=Optional[str])
@segment_id.validator
def check(self, _, value):
if value is None:
return
if not re.match(r'[\w\d_-]+', value):
raise ValueError('Malformed segment id "{}"'.format(value))
text = attr.ib(type=str)
@text.validator
def check(self, _, value):
if value is not None and normalize(value, self.normalization) != value:
raise ValueError('String "{}" is not normalized.'.format(value))
normalization = attr.ib(converter=Normalization, default=Normalization.NFC_SBB)
@classmethod
def from_text_segment(cls, text_segment, nsmap):
"""Build an ExtractedTextSegment from a PAGE content text element"""
segment_id = text_segment.attrib['id']
segment_text = None
with suppress(AttributeError):
segment_text = text_segment.find('./page:TextEquiv/page:Unicode', namespaces=nsmap).text
segment_text = segment_text or ''
segment_text = normalize_sbb(segment_text)
return cls(segment_id, segment_text)
def alto_namespace(tree):
"""Return the ALTO namespace used in the given ElementTree.
@ -117,12 +137,14 @@ def alto_extract(tree):
for line in tree.iterfind('.//alto:TextLine', namespaces=nsmap))
return ExtractedText(
(ExtractedTextSegment(None, normalize_sbb(line_text)) for line_text in lines),
'\n'
None,
(ExtractedText.from_text(normalize_sbb(line_text)) for line_text in lines),
'\n',
None
)
# FIXME hardcoded SBB normalization
# TODO This currently does not extract any segment id, because we are
# clueless about the ALTO format.
# FIXME needs to handle normalization
def alto_text(tree):
@ -157,20 +179,19 @@ def page_extract(tree):
region_id = region_ref_indexed.attrib['regionRef']
region = tree.find('.//page:TextRegion[@id="%s"]' % region_id, namespaces=nsmap)
if region is not None:
regions.append(ExtractedTextSegment.from_text_segment(region, nsmap))
regions.append(ExtractedText.from_text_segment(region, nsmap))
else:
warn('Not a TextRegion: "%s"' % region_id)
else:
raise NotImplementedError
else:
for region in tree.iterfind('.//page:TextRegion', namespaces=nsmap):
regions.append(ExtractedTextSegment.from_text_segment(region, nsmap))
regions.append(ExtractedText.from_text_segment(region, nsmap))
# Filter empty region texts
regions = (r for r in regions if r.text is not None)
return ExtractedText(regions, '\n')
# FIXME needs to handle normalization
return ExtractedText(None, regions, '\n', None)
def page_text(tree):
@ -180,8 +201,10 @@ def page_text(tree):
def plain_extract(filename):
with open(filename, 'r') as f:
return ExtractedText(
(ExtractedTextSegment('line %d' % no, line) for no, line in enumerate(f.readlines())),
'\n'
None,
[ExtractedText('line %d' % no, None, None, line) for no, line in enumerate(f.readlines())],
'\n',
None
)

38
qurator/dinglehopper/tests/extracted_text_test.py
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@ -1,17 +1,17 @@
import unicodedata
import pytest
from qurator.dinglehopper import ExtractedText, ExtractedTextSegment
from qurator.dinglehopper import ExtractedText
from uniseg.graphemecluster import grapheme_clusters
from qurator.dinglehopper import seq_align
from collections import namedtuple
def test_text():
test1 = ExtractedText([
ExtractedTextSegment('s0', 'foo'),
ExtractedTextSegment('s1', 'bar'),
ExtractedTextSegment('s2', 'bazinga')
], ' ')
test1 = ExtractedText(None, [
ExtractedText('s0', None, None, 'foo'),
ExtractedText('s1', None, None, 'bar'),
ExtractedText('s2', None, None, 'bazinga')
], ' ', None)
assert test1.text == 'foo bar bazinga'
assert test1.segment_id_for_pos(0) == 's0'
@ -21,8 +21,8 @@ def test_text():
def test_normalization_check():
with pytest.raises(ValueError, match=r'.*is not normalized.*'):
ExtractedTextSegment('foo', unicodedata.normalize('NFD', 'Schlyñ'))
assert ExtractedTextSegment('foo', unicodedata.normalize('NFC', 'Schlyñ'))
ExtractedText('foo', None, None, unicodedata.normalize('NFD', 'Schlyñ'))
assert ExtractedText('foo', None, None, unicodedata.normalize('NFC', 'Schlyñ'))
AlignmentElement = namedtuple('AlignmentElement', 'left right left_id right_id')
@ -36,17 +36,17 @@ def test_align():
not Python characters.
"""
test1 = ExtractedText([
ExtractedTextSegment('s0', 'foo'),
ExtractedTextSegment('s1', 'bar'),
ExtractedTextSegment('s2', 'batzinga')
], ' ')
test2 = ExtractedText([
ExtractedTextSegment('x0', 'foo'),
ExtractedTextSegment('x1', 'bar'),
ExtractedTextSegment('x2', '.'), # extra .
ExtractedTextSegment('x3', 'bazim̃ga'), # deletion + different grapheme cluster, m̃ also is two Python characters
], ' ')
test1 = ExtractedText(None, [
ExtractedText('s0', None, None, 'foo'),
ExtractedText('s1', None, None, 'bar'),
ExtractedText('s2', None, None, 'batzinga')
], ' ', None)
test2 = ExtractedText(None, [
ExtractedText('x0', None, None, 'foo'),
ExtractedText('x1', None, None, 'bar'),
ExtractedText('x2', None, None, '.'), # extra .
ExtractedText('x3', None, None, 'bazim̃ga'), # deletion + different grapheme cluster, m̃ also is two Python characters
], ' ', None)
left_pos = 0; right_pos = 0; alignment = []
for left, right in seq_align(grapheme_clusters(test1.text), grapheme_clusters(test2.text)):

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