175 lines
5.8 KiB
Python
175 lines
5.8 KiB
Python
import io
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import logging
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import tempfile
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from subprocess import DEVNULL, PIPE, Popen
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from typing import Iterable, Optional, Tuple
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import pandas as pd
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from docling_core.types.doc import BoundingBox, CoordOrigin
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from docling.datamodel.base_models import OcrCell, Page
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from docling.datamodel.pipeline_options import TesseractCliOcrOptions
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from docling.models.base_ocr_model import BaseOcrModel
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_log = logging.getLogger(__name__)
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class TesseractOcrCliModel(BaseOcrModel):
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def __init__(self, enabled: bool, options: TesseractCliOcrOptions):
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super().__init__(enabled=enabled, options=options)
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self.options: TesseractCliOcrOptions
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self.scale = 3 # multiplier for 72 dpi == 216 dpi.
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self._name: Optional[str] = None
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self._version: Optional[str] = None
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if self.enabled:
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try:
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self._get_name_and_version()
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except Exception as exc:
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raise RuntimeError(
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f"Tesseract is not available, aborting: {exc} "
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"Install tesseract on your system and the tesseract binary is discoverable. "
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"The actual command for Tesseract can be specified in `pipeline_options.ocr_options.tesseract_cmd='tesseract'`. "
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"Alternatively, Docling has support for other OCR engines. See the documentation."
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)
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def _get_name_and_version(self) -> Tuple[str, str]:
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if self._name != None and self._version != None:
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return self._name, self._version # type: ignore
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cmd = [self.options.tesseract_cmd, "--version"]
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proc = Popen(cmd, stdout=PIPE, stderr=PIPE)
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stdout, stderr = proc.communicate()
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proc.wait()
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# HACK: Windows versions of Tesseract output the version to stdout, Linux versions
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# to stderr, so check both.
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version_line = (
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(stdout.decode("utf8").strip() or stderr.decode("utf8").strip())
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.split("\n")[0]
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.strip()
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)
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# If everything else fails...
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if not version_line:
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version_line = "tesseract XXX"
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name, version = version_line.split(" ")
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self._name = name
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self._version = version
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return name, version
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def _run_tesseract(self, ifilename: str):
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cmd = [self.options.tesseract_cmd]
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if self.options.lang is not None and len(self.options.lang) > 0:
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cmd.append("-l")
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cmd.append("+".join(self.options.lang))
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if self.options.path is not None:
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cmd.append("--tessdata-dir")
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cmd.append(self.options.path)
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cmd += [ifilename, "stdout", "tsv"]
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_log.info("command: {}".format(" ".join(cmd)))
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proc = Popen(cmd, stdout=PIPE, stderr=DEVNULL)
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output, _ = proc.communicate()
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# _log.info(output)
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# Decode the byte string to a regular string
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decoded_data = output.decode("utf-8")
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# _log.info(decoded_data)
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# Read the TSV file generated by Tesseract
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df = pd.read_csv(io.StringIO(decoded_data), sep="\t")
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# Display the dataframe (optional)
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# _log.info("df: ", df.head())
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# Filter rows that contain actual text (ignore header or empty rows)
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df_filtered = df[df["text"].notnull() & (df["text"].str.strip() != "")]
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return df_filtered
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def __call__(self, page_batch: Iterable[Page]) -> Iterable[Page]:
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if not self.enabled:
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yield from page_batch
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return
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for page in page_batch:
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assert page._backend is not None
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if not page._backend.is_valid():
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yield page
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else:
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ocr_rects = self.get_ocr_rects(page)
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all_ocr_cells = []
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for ocr_rect in ocr_rects:
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# Skip zero area boxes
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if ocr_rect.area() == 0:
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continue
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high_res_image = page._backend.get_page_image(
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scale=self.scale, cropbox=ocr_rect
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)
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with tempfile.NamedTemporaryFile(
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suffix=".png", mode="w"
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) as image_file:
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fname = image_file.name
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high_res_image.save(fname)
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df = self._run_tesseract(fname)
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# _log.info(df)
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# Print relevant columns (bounding box and text)
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for ix, row in df.iterrows():
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text = row["text"]
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conf = row["conf"]
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l = float(row["left"])
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b = float(row["top"])
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w = float(row["width"])
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h = float(row["height"])
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t = b + h
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r = l + w
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cell = OcrCell(
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id=ix,
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text=text,
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confidence=conf / 100.0,
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bbox=BoundingBox.from_tuple(
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coord=(
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(l / self.scale) + ocr_rect.l,
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(b / self.scale) + ocr_rect.t,
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(r / self.scale) + ocr_rect.l,
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(t / self.scale) + ocr_rect.t,
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),
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origin=CoordOrigin.TOPLEFT,
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),
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)
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all_ocr_cells.append(cell)
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## Remove OCR cells which overlap with programmatic cells.
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filtered_ocr_cells = self.filter_ocr_cells(all_ocr_cells, page.cells)
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page.cells.extend(filtered_ocr_cells)
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# DEBUG code:
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# self.draw_ocr_rects_and_cells(page, ocr_rects)
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yield page
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