Docling/docling/models/tesseract_ocr_cli_model.py
Gaspard Petit d3f84b2457
fix: PermissionError when using tesseract_ocr_cli_model (#496)
Signed-off-by: Gaspard Petit <gaspardpetit@gmail.com>
2024-12-03 10:22:03 +01:00

185 lines
6.4 KiB
Python

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