RapidOCR ignores custom rec_keys.txt due to wrong parameter name in Docling

[Samkal2612]

Bug

When using RapidOCR through Docling, specifying a custom latin rec_keys.txt file still results in incorrect Chinese characters being returned on French documents.

I tested this using the Torch engine with the PP-OCRv3 latin .pth files, but I also reproduced the issue using other engines — so the problem is not engine-specific.

After investigation, the issue comes from a mismatch between the parameter name Docling sends to RapidOCR and what RapidOCR actually expects.

Docling passes:

"Rec.keys_path": rec_keys_path

But RapidOCR expects:

"Rec.rec_keys_path"

(See RapidOCR code in rapidocr/ch_ppocr_rec/main.py, line 51.)

Because of this mismatch, RapidOCR ignores the provided latin keys file and instead falls back to the default dictionary inside the package:

ppocr_keys_v1.txt

This default file contains Chinese characters, which explains why Chinese characters appear in the OCR output even when using latin models.

I confirmed that manually overriding the parameter to "Rec.rec_keys_path" fixes the issue and yields correct latin OCR results.

---

Steps to reproduce

1. Use Docling with RapidOCR enabled.
2. Use the Torch engine with PP-OCRv3 latin .pth recognition models
   (also reproducible with other engines).
3. Provide a latin recognition keys file (rec_keys.txt or equivalent).
4. Run OCR on a French document.
5. Observe that the output contains Chinese characters.
6. Override RapidOCR parameters with {"Rec.rec_keys_path": "<path_to_keys>"}.
7. Run OCR again → latin characters now appear correctly.

---

Docling version

2.63.0

Python version

3.12

[dosubot]

Hi @Samkal2612! I'm Dosu and I’m helping the docling team.

You're right—Docling 2.63.0 passes the parameter as "Rec.keys_path", but RapidOCR expects "Rec.rec_keys_path". Because of this mismatch, RapidOCR ignores your custom latin keys file and falls back to its default dictionary, which contains Chinese characters. That's why you see Chinese output even with latin models. This bug is present in 2.63.0 and affects all RapidOCR backends in Docling cite cite.

A workaround is available: you can override the parameter by passing a dictionary with the correct key in the rapidocr_params option. For example:

rapidocr_params = {"Rec.rec_keys_path": "<path_to_your_latin_rec_keys.txt>"}

Set this in your pipeline or model options, and RapidOCR will use your intended keys file cite.

There’s no official documentation for this workaround, but this approach is supported in recent Docling versions. If you encounter a "dict_url" error, make sure your RapidOCR config files are correct, as Docling can only pass the file path—RapidOCR itself must have the right config entries cite.

To reply, just mention @dosu.

---

^{How did I do? Good | Irrelevant | Incorrect | Verbose | Hallucination | Report 🐛 | Other}

   

[aditya0yadav]

Hi Sir,
Can i work upon this