---
language:
  - smp
  - sam
license: apache-2.0
library_name: kraken
tags:
  - ocr
  - htr
  - handwriting-recognition
  - ppocrv6
  - hebrew
  - samaritan
  - safetensors
  - oxygraphos-ocr
pipeline_tag: image-to-text
base_model:
  - PaddlePaddle/PP-OCRv6
datasets:
  - johnlockejrr/sam_44_mss_pango_metadata
---

# PP-OCRv6 Samaritan Hebrew recognizers

Line-level **text recognition** models for Samaritan Hebrew manuscripts,
trained with kraken’s PP-OCRv6 port (`ketos train --arch ppocrv6`) and usable
with [oxygraphos-ocr / Ppocrv6-OCR](https://github.com/johnlockejrr/oxygraphos-ocr)
(`ppocrv6-ocr`) or stock kraken ≥ 7.0.

These are **recognizers only** (line crops / baseline polygons). Pair with a
page segmenter for full-page OCR.

## Files

| File | Variant | Val char accuracy* | Codec | Size (approx.) | Notes |
|------|---------|--------------------|-------|----------------|-------|
| `ppocrv6_sam_heb_small.safetensors` | `small` | 0.9872 | 28 Hebrew letters + space | ~12 MB | From scratch |
| `ppocrv6_sam_heb_medium.safetensors` | `medium` | 0.9877 | 28 Hebrew letters + space | ~60 MB | From scratch |
| `ppocrv6_sam_heb_medium_ft.safetensors` | `medium` | 0.9886 | ~1622 chars (multilingual head retained) | ~61 MB | Fine-tuned from a multilingual PP-OCRv6 checkpoint |

\*Accuracy is the kraken checkpoint score embedded in the original `best_*.safetensors` filename (validation character accuracy).

**Default recommendation:** `ppocrv6_sam_heb_medium_ft.safetensors` for best accuracy on this domain. Use `small` when latency / footprint matters. Prefer the Hebrew-only `small` / `medium` codecs if you want a locked Samaritan alphabet (no Latin / punctuation emissions).

## Model details

| | |
|--|--|
| Architecture | `PPOCRv6Model` (kraken), task `recognition` |
| Input | RGB line images, target height **96**, baseline / polygon-dewarped lines (`seg_type: baselines`) |
| Normalization | NFD + whitespace normalize; BiDi reordering enabled at train time |
| Data | Samaritan Hebrew PAGE-XML line corpus (`sam_44_mss_pango` / additional split), compiled to binary Arrow |
| Min kraken | 7.0.0 (`_kraken_min_version` in metadata) |

Codec is stored inside each `.safetensors` file under `kraken_meta` — no sidecar alphabet file is required.

## Usage

### Download

```bash
hf download johnlockejrr/ppocrv6-sam-heb ppocrv6_sam_heb_medium_ft.safetensors --local-dir ./models
```

### oxygraphos-ocr / ppocrv6-ocr

```bash
ppocrv6-ocr -d cuda:0 infer \
  -m ./models/ppocrv6_sam_heb_medium_ft.safetensors \
  -f page --output-dir ./out page.xml
```

### kraken

```bash
kraken -i line.png text.txt ocr -m ./models/ppocrv6_sam_heb_medium_ft.safetensors
```

## Intended use

- Samaritan Hebrew manuscript line recognition (square Hebrew Unicode)
- Offline HTR pipelines that already produce line polygons / crops

## Limitations

- Not a page layout / line detector
- Trained on this manuscript family; other hands / scripts may need fine-tuning
- `medium_ft` retains a large multilingual output vocabulary; greedy decoding can occasionally emit non-Hebrew symbols on ambiguous lines
- Hebrew-only `small` / `medium` cannot emit characters outside their 28-letter (+ space) codec

## Training summary

- Trainer: kraken `ketos` / PP-OCRv6 (`AdamW+Muon`, cosine schedule, bf16-mixed)
- Augmentation on; `--base-dir R` / RTL-aware setup for Hebrew
- `medium` / `small`: trained from scratch on the Samaritan binary dataset
- `medium_ft`: fine-tuned from a multilingual medium checkpoint onto the same data (lower LR); final weights keep the large pretrained codec

## Citation / credits

- PP-OCR / PP-OCRv6: [PaddlePaddle/PaddleOCR](https://github.com/PaddlePaddle/PaddleOCR)
- kraken PP-OCRv6 port: [mittagessen/kraken](https://github.com/mittagessen/kraken)
- Packaging: [johnlockejrr/oxygraphos-ocr](https://github.com/johnlockejrr/oxygraphos-ocr) (`Ppocrv6-OCR`)

## License

Apache-2.0 (weights and card). Upstream PaddleOCR / kraken licenses still apply to those codebases.