Ask HN: OCR for 100 year old (German) handwritten cursive script?

#1

Post by jbverschoor » Mon, Jan 15, 2024, 7:08 PM UTC

I'm looking for an OCR solution for about 200 pages of text. It's handwritten German script from about 100 years old and I can barely read the handwriting myself. Google Translate sometimes manages to OCR certain parts, but nothing useful (I don't need the translation part of GT). Which solutions out there would be able to recognize old handwritten script?

Re: Ask HN: OCR for 100 year old (German) handwritten cursive script?

#2

Post by robertknight » Mon, Jan 15, 2024, 7:40 PM UTC

You could try something like https://aws.amazon.com/textract/ or https://cloud.google.com/vision/docs/handwriting. Both have support for modern handwriting. I don't know if it will work with a script written a century ago though.

Re: Ask HN: OCR for 100 year old (German) handwritten cursive script?

#3

Post by sandreas » Mon, Jan 15, 2024, 7:59 PM UTC

You can train Tesseract to recognize Handwriting[1], but the first and most important step would be the preprocessing of your documents. I would recommend to start with a local adaptive thresholding algorithm[2] like Sauvola for binarization. The preprocessing steps would be[3]

  1) Binarization
  2) Skew Correction
  3) Noise Removal
  4) Thinning and Skeletonization

Probably you are facing "Sütterlin"[4], which differs quite a bit from modern german handwriting.

In your case (only 200 pages) it might be easier to use template matching[5] to identify similar characters and just "transliterate" matches into modern printed letters (like an overlay over the original text). This way you would have a quick solution while still being accurate enough to just read it.

[1]: https://tesseract-ocr.github.io/tessdoc/#training-for-tesser...

[2]: https://brandonmpetty.github.io/Doxa/WebAssembly/

[3]: https://towardsdatascience.com/pre-processing-in-ocr-fc231c6...

[4]: https://de.wikipedia.org/wiki/S%C3%BCtterlinschrift

[5]: https://docs.opencv.org/3.4/d4/dc6/tutorial_py_template_matc...

Re: Ask HN: OCR for 100 year old (German) handwritten cursive script?

#4

Post by lainga » Mon, Jan 15, 2024, 8:04 PM UTC

Does it look like Sütterlin? Are you familiar with it?

[] https://en.wikipedia.org/wiki/S%C3%BCtterlin

Re: Ask HN: OCR for 100 year old (German) handwritten cursive script?

#5

Post by 082349872349872 » Mon, Jan 15, 2024, 8:04 PM UTC

robertknight wrote: post #2

You could try something like https://aws.amazon.com/textract/ or https://cloud.google.com/vision/docs/handwriting . Both have support for modern handwriting. I don't know if it will work with a script written a century ago though.

if it's https://en.wikipedia.org/wiki/Sütterlin I doubt anything trained on current script would make any more sense of it than we do

Re: Ask HN: OCR for 100 year old (German) handwritten cursive script?

#6

Post by sneak » Mon, Jan 15, 2024, 8:04 PM UTC

For only 200 pages, I’d farm it out to humans.

Re: Ask HN: OCR for 100 year old (German) handwritten cursive script?

#7

Post by huijzer » Mon, Jan 15, 2024, 8:09 PM UTC

I threw some German medical handwriting images into ChatGPT a while back and asked it to transcribe it and it worked pretty well. ChatGPT knows a lot about language so that helped in filling in the gaps.