poster2json

Convert scientific posters (PDF/images) to structured JSON metadata using Large Language Models.

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Description

poster2json extracts structured metadata from scientific conference posters (PDF or image format) into machine-actionable JSON conforming to the poster-json-schema.

The pipeline uses:

Llama-3.1-8B-Instruct (a verbatim mirror of Meta's release; swap with any HuggingFace instruct model via --model) for JSON structuring
Qwen2-VL-7B for vision-based OCR of image posters
pdfplumber for layout-aware PDF text extraction
lingua-language-detector for ISO 639-1 language detection on body text (overrides any value the model emits — body text beats metadata-fragment guessing)
ROR (https://api.ror.org) for affiliation canonicalisation; matched names get a ROR identifier attached

Quick Start

Installation

pip install poster2json

CLI Usage

# Extract metadata from a poster (default: Llama-3.1-8B-Instruct @ 4bit)
poster2json extract poster.pdf -o result.json

# Use a different instruct model (any HuggingFace repo id works)
poster2json extract poster.pdf --model google/gemma-2-9b-it --quantization 4bit

# Trade VRAM for quality
poster2json extract poster.pdf --quantization 8bit
poster2json extract poster.pdf --quantization fp16

# Validate extracted JSON
poster2json validate result.json

# Process multiple posters
poster2json batch ./posters/ -o ./output/

Python API

from poster2json import extract_poster, validate_poster

# Extract metadata
result = extract_poster("poster.pdf")
print(result["titles"][0]["title"])

# Validate the result
is_valid = validate_poster(result)

Output Format

Output conforms to the poster-json-schema (DataCite 4.7):

{
  "$schema": "https://posters.science/schema/v0.2/poster_schema.json",
  "creators": [
    {
      "name": "Garcia, Sofia",
      "givenName": "Sofia",
      "familyName": "Garcia",
      "affiliation": [
        {
          "name": "Stanford University",
          "affiliationIdentifier": "https://ror.org/00f54p054",
          "affiliationIdentifierScheme": "ROR",
          "schemeURI": "https://ror.org/"
        }
      ]
    }
  ],
  "titles": [
    { "title": "Machine Learning Approaches to Diabetic Retinopathy Detection" }
  ],
  "publicationYear": null,
  "language": "en",
  "researchField": "Health Sciences",
  "subjects": [
    { "subject": "Machine Learning" },
    { "subject": "Diabetic Retinopathy" }
  ],
  "descriptions": [
    { "description": "We present a deep learning model...", "descriptionType": "Other" }
  ],
  "publisher": null,
  "content": {
    "sections": [
      { "sectionTitle": "Abstract", "sectionContent": "..." },
      { "sectionTitle": "Methods", "sectionContent": "..." },
      { "sectionTitle": "Results", "sectionContent": "..." }
    ]
  },
  "imageCaptions": [{ "id": "fig1", "caption": "Figure 1. ROC curves showing..." }],
  "tableCaptions": [{ "id": "table1", "caption": "Table 1. Performance metrics" }],
  "formats": ["application/pdf"]
}

Notes on the auto-populated fields:

language is detected from the raw body text (lingua heuristic). Returns null when text is too short (<200 chars / <50 non-ASCII codepoints) or the detector is unsure.
researchField must be one of the four OpenAlex top-level domains: Health Sciences, Life Sciences, Physical Sciences, Social Sciences. Null when the model can't pick one confidently.
affiliation gets ROR enrichment when the matcher returns a high-confidence chosen result. Strings without a confident match pass through unchanged. Set POSTER2JSON_ROR=0 to disable.
publisher and publicationYear are always emitted as null. They are platform-owned and set when the poster is published, not by extraction.
formats is derived from the input file's extension, not the model.

System Requirements

Requirement	Specification
GPU	NVIDIA CUDA-capable, ≥8GB VRAM (default 4bit); ≥16GB for `--quantization fp16` or image/OCR posters
RAM	≥32GB recommended
Python	3.10+
OS	Linux, macOS, Windows (via WSL2)

Performance

Validated on 20 manually annotated scientific posters (19 PDF via pdfplumber, 1 image via vision OCR):

Metric	Score	Threshold
Word Capture	0.92	≥0.75
ROUGE-L	0.85	≥0.75
Number Capture	0.97	≥0.75
Field Proportion	0.88	0.50–1.50

Pass Rate: 19/20 (95%). The single failure is a dense table/flowchart poster whose reference annotation splits one visual region into many fine-grained sections.

Documentation

Document	Description
Architecture	Technical details & methodology
Evaluation	Validation metrics & results

Development Setup

# Clone the repository
git clone https://github.com/fairdataihub/poster2json.git
cd poster2json

# Create a virtual environment
python -m venv .venv

# Activate the virtual environment
source venv/bin/activate
.venv\Scripts\activate # On Windows

# Install poetry
pip install poetry

# Install dependencies
poetry install

# Run tests
poe test

# Format code
poe format

If you are on windows and have multiple python versions, you can use the following commands:

py -0p # list all python versions

py -3.12 -m venv .venv

License

MIT License - see LICENSE for details.

Citation

@software{poster2json2026,
  title = {poster2json: Scientific Poster to JSON Metadata Extraction},
  author = {O'Neill, James and Soundarajan, Sanjay and Portillo, Dorian and Patel, Bhavesh},
  year = {2026},
  version = {0.8.0},
  url = {https://github.com/fairdataihub/poster2json},
  doi = {10.5281/zenodo.18320010}
}

Funding

This project is funded by The Navigation Fund (10.71707/rk36-9x79).

Contributing

Contributions welcome! Please see CONTRIBUTING.md for guidelines.

Release files for poster2json 0.9.23

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for poster2json 0.9.23
File	Size	Uploaded
poster2json-0.9.23.tar.gz	80.2 kB	Jul 7, 2026	Details

Built distribution (wheel)

Table of built distributions (wheels) for poster2json 0.9.23
File	Interpreter	ABI	Platform	Reset
poster2json-0.9.23-py3-none-any.whl 85.1 kB Jul 7, 2026	Python 3	none	any	Details

Total release size: 165.4 kB

Release files / poster2json-0.9.23.tar.gz

Download URL	poster2json-0.9.23.tar.gz
Size	80.2 kB
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Uploaded via	`poetry/2.4.1 CPython/3.12.13 Linux/6.17.0-1018-azure`

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Download URL	poster2json-0.9.23-py3-none-any.whl
Size	85.1 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`c9a0032ae8d5031417a57ff28aeb642e2501d4b1ce61938c3c7e57bc0af42a5e`
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Upload date	Jul 7, 2026
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Uploaded via	`poetry/2.4.1 CPython/3.12.13 Linux/6.17.0-1018-azure`