LX Anonymizer

LX Anonymizer is a comprehensive toolkit for de-identifying endoscopy frames and medical reports. It combines advanced OCR pipelines, spaCy-based NER, heuristic sanitizers, and report-specific rules to redact or pseudonymize sensitive information while preserving clinical context.

Core Components

ReportReader

Specialized for medical report anonymization with support for:

• Multi-format processing: PDFs and images with automatic OCR fallback
• Advanced metadata extraction: LLM-powered extraction using DeepSeek, MedLLaMA, or Llama3
• Ensemble OCR: Combines Tesseract and TrOCR for improved accuracy
• PDF anonymization: Creates blackened PDFs with sensitive regions automatically masked
• Batch processing: Handles multiple reports with comprehensive error handling

FrameCleaner

Designed for real-time video frame anonymization featuring:

• Hardware-accelerated processing: NVIDIA NVENC support with CPU fallback
• Streaming video processing: Processes videos without full re-encoding when possible
• Adaptive frame sampling: Optimizes performance for long videos (>10,000 frames)
• Multiple anonymization strategies: Frame removal or mask overlay techniques
• ROI-based masking: Device-specific region masking for endoscopic equipment

Default Return Format

LX Anonymizer will return a sensitive meta compliant dict when running either of the main client functions above.

Highlights

• End-to-end anonymization of PDFs and video sequences using OCR, NER, and pseudonymization helpers.
• Modular pipeline that lets you choose between Tesseract, TrOCR, ensemble OCR, and multiple metadata extractors.
• Hardware optimization with NVENC acceleration for real-time video processing and streaming capabilities.
• Human-in-the-loop ready outputs: original/anonymized text side by side, metadata JSON, and validation artefacts.
• Extensible ruleset covering device-specific renderers, fuzzy name matching, and language-specific replacements.

Requirements

• Python 3.12+
• Linux or macOS (Windows support is experimental)
• NVIDIA GPU recommended for real-time video anonymization (CUDA 12.x). CPU-only processing works but is slower.
• Optional extras:
  • spaCy de_core_news_sm model for German NER. Source installs with uv use the locked model wheel; other runtime environments may need an explicit install.
  • Torch vision/audio for video OCR workloads
  • local or remote LLM-backed metadata extraction

Installation

From Nix

The repository exposes flake packages and can be consumed directly from another project's devenv.yaml:

inputs:
  lx-anonymizer:
    url: github:wg-lux/lx-anonymizer

After adding the input, reference the package through your own devenv.nix or flake outputs. You do not need to commit or publish local result or result-app symlinks for this to work.

From PyPI

pip install lx-anonymizer

The base package installs the public API, CLI, PDF/image processing, spaCy-based metadata extraction, and PyTesseract fallback OCR. Install extras only when you need the corresponding feature set:

pip install "lx-anonymizer[ocr]"      # RapidOCR, TesserOCR, TrOCR, CRAFT helpers
pip install "lx-anonymizer[llm]"      # LLM client-side helpers
pip install "lx-anonymizer[nlu]"      # Flair NER
pip install "lx-anonymizer[training]" # PHI-region detector training helpers
pip install "lx-anonymizer[django]"   # Django integration
pip install "lx-anonymizer[dev]"      # local development tooling

From source

git clone https://github.com/wg-lux/lx-anonymizer.git
cd lx-anonymizer
uv sync
uv sync --extra cpu  # CPU-only PyTorch-dependent features
uv sync --extra gpu  # CUDA 12.8 PyTorch-dependent features

The cpu and gpu extras are mutually exclusive in uv. The CPU extra routes torch, torchaudio, and torchvision to PyTorch's CPU wheel index; the GPU extra routes them to PyTorch's CUDA 12.8 wheel index and adds onnxruntime-gpu.

Nix development shell

direnv allow
nix develop

This loads GPU, OCR, and tooling dependencies declared in devenv.nix.

Packaging

Python package

PyPI releases now use a split artifact strategy:

• platform wheels are built in GitHub Actions with maturin and include the Rust extension
• the source distribution is still built from pyproject.toml with python -m build --sdist

For a local source-package sanity check:

uv build --sdist
uv run python scripts/audit_distribution.py dist/*.tar.gz

If you build the local wheel on a non-manylinux host (for example Nix), pass the desired compatibility target explicitly:

make pypi-wheel PYPI_COMPATIBILITY=manylinux_2_34

CI uses maturin --manylinux auto via PyO3/maturin-action to produce the published Linux wheels.

The published Python package remains the baseline install path, with optional feature sets enabled through extras such as [ocr], [llm], [nlu], and [training]. Development and build tools such as pre-commit, ziglang, and type stub packages are intentionally kept out of the runtime dependency set.

Native extension

The repository also contains an optional Rust extension used for local and Nix packaging. The Python code loads it opportunistically through lx_anonymizer._native and falls back to pure Python implementations when the native module is unavailable or only partially implemented.

PyPI wheels built by CI now include this extension. Pure-Python fallback still exists for environments that install from source without a compiled native module.

Local prebuilt extension files, generated reports, study data, and cache files are excluded from PyPI artifacts. CI audits each wheel and sdist before upload.

Nix packages

The flake exports multiple package variants, including the base CLI package and a native-enabled package:

nix build .#lx-anonymizer
nix build .#lx-anonymizer-with-native

Those commands create local ./result symlinks for inspection on your machine. They are build outputs, not repository contents, and should remain uncommitted.

Release guidance

• Use uv build --sdist and uv run python scripts/audit_distribution.py dist/*.tar.gz to validate the source distribution locally.
• Use GitHub Actions to build release wheels with maturin.
• Use nix build .#lx-anonymizer or nix build .#lx-anonymizer-with-native to validate flake packaging.
• Do not commit result or result-app.
• Configure PyPI trusted publishing before the first tagged release.
• Prefer a TestPyPI dry run before the first production PyPI publication.

Release workflow

The intended release path is now:

1. Push a branch and let CI build wheels and the sdist.
2. Verify the wheel smoke tests pass on Linux and macOS.
3. Run a TestPyPI publication from the release workflow if this is the first native-wheel release.
4. Tag vX.Y.Z to trigger the production publish workflow.

The release workflow publishes:

• native wheels built with maturin
• an sdist built with python -m build --sdist

Configuration

Settings are loaded from environment variables and an optional .env file. See SETTINGS.md for a quick overview and example configuration.

Model downloads

The default German spaCy model is de_core_news_sm. On first use, LX Anonymizer loads the model if it is installed and otherwise downloads it with the same Python interpreter that is running the application. To pre-install it, run:

python -m spacy download de_core_news_sm

Clinical/strict deployments fail loudly when the configured model is missing. Automatic download is enabled by default. Set LX_ANONYMIZER_SPACY_AUTO_DOWNLOAD=0 or SPACY_AUTO_DOWNLOAD=False to disable network installation. Outside clinical/strict profiles, disabling it permits the degraded blank fallback.

Start a compatible LLM server exposing either an OpenAI-compatible API or Ollama:

# Default local Gemma 4 setup used for OCR and text recognition
bash scripts/provision_ollama_gemma4.sh
# In a devenv shell, the equivalent task is:
devenv tasks run ollama:provision-gemma4

# Alternative high-throughput setup
vllm serve Qwen/Qwen3.5-9B --port 8000

Caution: This is only recommended on devices with sufficient gpu capabilities

The EAST detector now downloads on first use, not on import. TrOCR and other optional OCR assets download only when those paths are exercised. For air-gapped deployments, pre-seed the required model files before running the relevant pipeline steps.

Quickstart

CLI Usage

Image / PDF Pipeline

# Process a single image or PDF with the packaged console script
lx-anonymizer -i report.pdf

# Use a custom EAST model and device profile
lx-anonymizer -i frame.png -east /models/frozen_east_text_detection.pb -d olympus_cv_1500

# Return validation metadata in addition to the output path
lx-anonymizer -i report.pdf -V

Useful CLI options:

• -d/--device selects the device profile used for ROI handling.
• -c/--min-confidence, -w/--width, and -e/--height tune EAST detection.
• -V/--validation returns extra validation metadata.
• python -m lx_anonymizer.cli --help shows the same CLI help as lx-anonymizer --help.

Python API

It is recommended to call the python api. Here, the main integration is with the endoreg-db package that is tightly integrated with lx-anonymizer to provide a private medical database.

ReportReader API

import hashlib
from pathlib import Path
from uuid import uuid4

from lx_anonymizer import ReportReader
from lx_anonymizer.report_contracts import (
    ReportAnonymizationOptions,
    ReportAnonymizationRequest,
)

source_path = Path("/path/to/report.pdf")
source_bytes = source_path.read_bytes()
attempt_directory = Path("/path/to/attempt")
attempt_directory.mkdir(parents=True)

request = ReportAnonymizationRequest(
    attempt_id=uuid4(),
    source_path=source_path,
    source_sha256=hashlib.sha256(source_bytes).hexdigest(),
    source_size_bytes=len(source_bytes),
    output_directory=attempt_directory,
    options=ReportAnonymizationOptions(use_ensemble=True, use_llm=True),
)

reader = ReportReader(locale="de_DE")
result = reader.process_report(request)
print(result.artifact_path, result.artifact_sha256)

# Advanced processing with region cropping
original, anonymized, meta, cropped_regions, anonymized_pdf = reader.process_report_with_cropping(
    pdf_path="/path/to/report.pdf",
    crop_output_dir="/path/to/cropped_regions",
    crop_sensitive_regions=True,
    use_llm=True
)

ReportReader is the canonical report-oriented entry point for immutable PDF snapshots.

ReportReader(...) constructor:

• report_root_path: optional base path for report assets.
• locale: Faker locale for pseudonymized replacements.
• employee_first_names / employee_last_names: optional replacement pools.
• flags: optional parsing markers merged with DEFAULT_SETTINGS["flags"].
• text_date_format: output format used for anonymized date text.

process_report(...) accepts one strictly validated ReportAnonymizationRequest. The caller supplies the immutable source identity, an attempt-owned output directory, and processing options. The method always creates and validates an anonymized PDF without choosing a canonical publication path.

It returns a frozen ReportAnonymizationResult containing original and anonymized text, typed sensitive metadata, the attempt-local artifact path, artifact size and SHA-256, structural PDF validation, and anonymizer provenance.

process_report_with_cropping(...) is a separate diagnostic helper with:

• crop_output_dir: where cropped sensitive regions are written.
• crop_sensitive_regions: enable or disable crop extraction.
• anonymization_output_dir: output directory for the crop-based anonymized PDF.

process_report_with_cropping(...) returns:

• original_text
• anonymized_text
• report_meta
• cropped_regions_info: mapping of cropped sensitive regions.
• anonymized_pdf_path: Path | None

FrameCleaner API

from lx_anonymizer.frame_cleaner import FrameCleaner
from pathlib import Path

# Initialize with hardware acceleration
cleaner = FrameCleaner(use_llm=True)

# Clean video with mask overlay (preserves all frames)
cleaned_path, metadata = cleaner.clean_video(
    video_path=Path("endoscopy.mp4"),
    endoscope_image_roi={"x": 550, "y": 0, "width": 1350, "height": 1080},
    endoscope_data_roi_nested={"patient_info": {"x": 10, "y": 10, "width": 300, "height": 50}},
    technique="mask_overlay"
)

# Remove sensitive frames entirely
cleaned_path, metadata = cleaner.clean_video(
    video_path=Path("endoscopy.mp4"),
    endoscope_image_roi=roi_config,
    endoscope_data_roi_nested=data_roi_config,
    technique="remove_frames"
)

FrameCleaner is the video-oriented entry point for endoscopy footage and frame-level overlays.

FrameCleaner(...) constructor:

• use_llm: enables provider-backed batch metadata enrichment when available.
• use_minicpm and minicpm_config: reserved for optional OCR backends.

clean_video(...) parameters:

• video_path: input video file.
• endoscope_image_roi: flat ROI dict for the visible endoscope image, typically with x, y, width, height.
• endoscope_data_roi_nested: nested ROI mapping for text-bearing overlay regions such as patient info blocks.
• output_path: optional explicit output path.
• technique: one of mask_overlay, remove_frames, or extract_only.
• device: device profile name, defaulting to olympus_cv_1500.

clean_video(...) behavior by technique:

• mask_overlay: preserves the timeline and overlays masks onto sensitive regions.
• remove_frames: drops sensitive frames and rewrites the stream.
• extract_only: does metadata extraction without producing a masked/removal-focused anonymization pass.

clean_video(...) returns:

• output_video_path: resulting video path. With extract_only, this is still the path chosen for the run.
• sensitive_meta: accumulated metadata dictionary extracted from sampled frames.

ROI guidance:

• Use endoscope_image_roi for the main picture area that may need masking.
• Use endoscope_data_roi_nested for device-specific overlay fields.
• The helper stack normalizes common ROI key variants, but using x, y, width, height directly is the least ambiguous form.

See tests/test_report_reader_init.py and tests/test_frame_cleaner.py for concrete usage patterns.

Advanced Features

ReportReader Capabilities

• Intelligent OCR Fallback: Automatically switches to OCR when PDF text extraction yields poor results
• Multi-LLM Support: DeepSeek, MedLLaMA, and Llama3 integration for enhanced medical entity extraction
• Ensemble OCR: Combines multiple OCR engines (Tesseract + TrOCR) for improved accuracy
• PDF Anonymization: Creates masked PDFs with sensitive regions automatically blackened
• Batch Processing: Processes multiple reports with error recovery and progress tracking
• Metadata Validation: Cross-validates extracted information using multiple extraction methods

FrameCleaner Capabilities

• Adaptive Sampling: Automatically samples frames for long videos (>10,000 frames) to optimize performance
• Hardware Acceleration: NVIDIA NVENC support with automatic CPU fallback for unsupported systems
• Streaming Processing: Uses FFmpeg streaming and named pipes to minimize memory usage and processing time
• ROI-based Processing: Device-specific region configurations for endoscopic equipment (Olympus CV-1500, etc.)
• Multiple Anonymization Strategies:
  • Mask Overlay: Blacks out sensitive regions while preserving video timeline
  • Frame Removal: Completely removes sensitive frames from the video stream
• Quality Optimization: Automatic pixel format conversion and codec selection for minimal quality loss

Performance Optimizations

• Stream Copy Operations: Avoids re-encoding when possible, using FFmpeg's -c copy for maximum speed
• Named Pipe Support: In-memory video streaming for frame removal operations
• Batch Metadata Extraction: Processes multiple frames simultaneously for improved efficiency
• Hardware Detection: Automatically detects and uses available hardware acceleration (NVENC, QuickSync)

Data directories

By default, outputs live in ~/etc/lx-anonymizer/{data,temp}. Adjust them in lx_anonymizer/setup/directory_setup.py. Clean temp regularly to avoid large intermediate artefacts.

Development workflow

• Code quality: uv run flake8 for linting and formatting
• Testing:
  • CPU-friendly tests: uv run pytest -m "not gpu"
  • GPU-accelerated tests: uv run pytest -m gpu (requires CUDA-capable hardware)
  • Integration tests: uv run pytest tests/test_cli_integration.py
  • Frame processing tests: uv run pytest tests/test_frame_cleaner.py
• Performance profiling: Use --log-level DEBUG for detailed timing information
• Build: uv run python -m build --sdist for local sdist validation; GitHub Actions builds release wheels
• Full validation: scripts/run_checks.sh for comprehensive local testing

Testing Medical Workflows

• ReportReader: Test with sample medical PDFs in German and English
• FrameCleaner: Validate with endoscopic video files (MP4, AVI formats supported)
• Integration: Use example_anonymize_pdf.py for end-to-end testing scenarios

Project roadmap

1. Release Management:
   • Continue hardening native-wheel publishing across release targets
   • Continue separating optional GPU/LLM workloads behind extras
   • Extend release automation with GitHub release notes and TestPyPI promotion flow
2. API Enhancement:
   • Expose REST/gRPC service with validation UI
   • WebSocket support for real-time video processing
   • Enhanced batch processing APIs
3. Performance & Scalability:
   • Distributed processing support for large video collections
   • Advanced caching mechanisms for repeated processing
   • Multi-GPU support for FrameCleaner operations
4. Medical Workflow Integration:
   • DICOM support for medical imaging workflows
   • HL7 FHIR integration for healthcare systems
   • Advanced medical entity recognition models

Contributing

See CONTRIBUTING.md for contribution guidelines, testing instructions, and communication channels.

License

Released under the MIT License.

Contact

Questions? Email lux@coloreg.de .