saraldocling 1.0.1

Fast PDF text and image/table extraction using PyMuPDF + YOLOv8 DocLayNet ONNX

SARAL Docling

Fast PDF text and image/table extraction.
Powered by PyMuPDF + YOLOv8 DocLayNet (bundled) — no model file needed.

pip install saraldocling
saraldocling paper.pdf

License: This package bundles yolov8n-doclaynet.onnx which is released under AGPL-3.0. The entire saraldocling package is therefore also distributed under AGPL-3.0.
Full text: https://www.gnu.org/licenses/agpl-3.0.html

No OCR. Only PDFs with a native text layer are supported.
For scanned PDFs, pre-process with ocrmypdf first (see Limitations).

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Table of contents

• How it works
• Installation
• CLI usage
• Python API
• Output structure
• FastAPI / server deployment
• Configuration reference
• Limitations

---

How it works

Stage	What happens
1 — Text	PyMuPDF extracts the native text layer from every page
2 — Images/Tables	YOLOv8 DocLayNet (bundled ONNX) detects Picture and Table regions, re-renders those regions at 300 DPI, and saves them as PNGs

The ONNX model (yolov8n-doclaynet.onnx) is included inside the wheel — there is no separate download step.

---

Installation

onnxruntime is included by default (CPU). For GPU, use [gpu] instead. Do not install both — the two onnxruntime builds conflict.

Default (CPU) — works everywhere, no GPU required

pip install saraldocling

GPU — NVIDIA CUDA

Requires CUDA 11.8+ and cuDNN on the host.
Compatibility: https://onnxruntime.ai/docs/execution-providers/CUDA-ExecutionProvider.html

pip install "saraldocling[gpu]"

Apple Silicon — CoreML acceleration (M1/M2/M3/M4)

The default install works fine on ARM. For ANE-accelerated inference:

pip install saraldocling
pip install onnxruntime-silicon      # replaces the cpu wheel

Linux / Debian server — one-time system packages

sudo apt-get install -y libgl1 libglib2.0-0
pip install saraldocling

From source (development)

git clone https://github.com/yourname/saraldocling
cd saraldocling
pip install -e ".[dev]"

---

CLI usage

The bundled model runs automatically. No --model flag needed.

# Full pipeline: text + image/table crops (default)
saraldocling paper.pdf

# Text only — skip YOLO, much faster
saraldocling paper.pdf --no-images

# Custom output directory
saraldocling paper.pdf -o ./results

# Preview extracted text in the terminal
saraldocling paper.pdf --preview 800

# One .txt file per page
saraldocling paper.pdf --pages

# GPU (CUDA) — needs saraldocling[gpu]
saraldocling paper.pdf --gpu

# Apple Silicon CoreML
saraldocling paper.pdf --coreml

# Debug: see every step logged
saraldocling paper.pdf -v

# All flags
saraldocling --help

What gets written

paper_out/
├── extracted_text.txt        ← all pages joined
├── manifest.json             ← JSON summary of the run
├── pages/                    ← only with --pages
│   ├── page_001.txt
│   └── page_002.txt
└── extracted_images/         ← Picture + Table crops at 300 DPI
    ├── p0_Picture_231.png
    └── p2_Table_445.png

Output directory is auto-named <pdf_stem>_out/ next to the PDF unless you pass -o.

---

Python API

One-call pipeline (recommended)

from saraldocling import parse_pdf, ParseConfig

# Full pipeline — bundled model used automatically
result = parse_pdf(ParseConfig(
    pdf_path="paper.pdf",
    output_dir="./out",
))

print(result.num_pages)       # int
print(result.text[:500])      # full extracted text
print(result.image_paths)     # list[str] of saved PNG paths

# Text only — skip YOLO
result = parse_pdf(ParseConfig(
    pdf_path="paper.pdf",
    output_dir="./out",
    extract_images=False,
))

Lower-level: text extraction only

from saraldocling import PDFProcessor

with PDFProcessor("paper.pdf") as proc:
    full_text  = proc.extract_text()
    page_text  = proc.extract_text_by_page(1)      # 0-indexed
    page_image = proc.extract_page_image(0, dpi=150)  # PIL.Image

Lower-level: YOLO extraction only

from saraldocling import ImageExtractor

# CPU (default)
with ImageExtractor() as ext:
    paths = ext.extract_images_from_pdf("paper.pdf", "./out")

# GPU
with ImageExtractor(providers=["CUDAExecutionProvider", "CPUExecutionProvider"]) as ext:
    paths = ext.extract_images_from_pdf("paper.pdf", "./out")

# Apple Silicon
with ImageExtractor(providers=["CoreMLExecutionProvider", "CPUExecutionProvider"]) as ext:
    paths = ext.extract_images_from_pdf("paper.pdf", "./out")

Using a custom model (advanced)

result = parse_pdf(ParseConfig(
    pdf_path="paper.pdf",
    output_dir="./out",
    model_path="/path/to/custom.onnx",   # overrides the bundled model
))

---

Output structure

manifest.json example:

{
  "pdf": "/abs/path/to/paper.pdf",
  "pages": 12,
  "text_chars": 38201,
  "text_file": "/abs/path/to/paper_out/extracted_text.txt",
  "per_page_files": [],
  "image_paths": [
    "/abs/path/to/paper_out/extracted_images/p0_Picture_231.png",
    "/abs/path/to/paper_out/extracted_images/p3_Table_112.png"
  ]
}

Crop filenames follow the pattern p<page>_<Label>_<x>.png where <Label> is either Picture or Table.

---

FastAPI / server deployment

saraldocling is a plain pip package — drop it into any FastAPI app on Debian with no special system configuration beyond the apt packages above.

Minimal endpoint

# main.py
import shutil, uuid
from pathlib import Path

from fastapi import FastAPI, File, UploadFile
from fastapi.responses import JSONResponse
from saraldocling import parse_pdf, ParseConfig

OUTPUT_ROOT = Path("/tmp/saraldocling")

app = FastAPI()

@app.post("/parse")
async def parse(file: UploadFile = File(...)):
    job_dir = OUTPUT_ROOT / str(uuid.uuid4())
    job_dir.mkdir(parents=True, exist_ok=True)
    pdf_path = job_dir / file.filename

    with open(pdf_path, "wb") as f:
        shutil.copyfileobj(file.file, f)

    result = parse_pdf(ParseConfig(
        pdf_path=str(pdf_path),
        output_dir=str(job_dir),
    ))

    return JSONResponse({
        "pages":       result.num_pages,
        "text":        result.text,
        "image_paths": result.image_paths,
    })

pip install saraldocling fastapi uvicorn python-multipart
uvicorn main:app --host 0.0.0.0 --port 8000

Pre-load the ONNX session at startup

Creating an ImageExtractor loads and optimises the ONNX graph (~300 ms). Do this once at startup and reuse it — session.run() is thread-safe:

from contextlib import asynccontextmanager
from fastapi import FastAPI
from saraldocling import ImageExtractor

extractor: ImageExtractor | None = None

@asynccontextmanager
async def lifespan(app: FastAPI):
    global extractor
    extractor = ImageExtractor()      # loads bundled model
    yield
    extractor.close()

app = FastAPI(lifespan=lifespan)

# then in your endpoint, call extractor.extract_images_from_pdf() directly

---

Configuration reference (ParseConfig)

Field	Default	Description
pdf_path	required	Path to the source PDF
output_dir	required	Root directory for all output files
extract_images	True	Run YOLO stage. False = text only
model_path	None	Custom .onnx path. None = use bundled model
conf_threshold	0.30	YOLO confidence cutoff
nms_threshold	0.45	NMS IoU cutoff
min_box_size	30	Minimum crop side-length in pixels
num_workers	cpu_count	Thread-pool size for page processing
onnx_providers	["CPUExecutionProvider"]	ONNX Runtime execution providers

---

DocLayNet labels

The model detects 11 document element types.
Only Picture and Table regions are saved as crops.

Caption   Footnote   Formula   List-item   Page-footer
Page-header   Picture   Section-header   Table   Text   Title

---

Limitations

Not OCR — requires a native text layer in the PDF. For scanned documents:

pip install ocrmypdf
ocrmypdf scanned.pdf scanned_ocr.pdf
saraldocling scanned_ocr.pdf

Thread safety — both PDFProcessor and ImageExtractor use internal mutex locks (mirroring the Go SafeDocument). Safe for concurrent use.

---

License

This package is distributed under AGPL-3.0 because it bundles yolov8n-doclaynet.onnx, which carries that licence.

What this means in practice:

• Free to use for any purpose, including commercial.
• If you modify the source and run it as a network service, you must make your modified source available under AGPL-3.0.
• The full licence text is at https://www.gnu.org/licenses/agpl-3.0.html