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Extracting text from an image using Ocropus

63 points by danvk 12y ago

iskander 12y ago
I wonder if it's possible to remove the need for post-processing of the LSTM's output by integrating transcription into the neural network model directly.
- danvk 12y ago
  The first row of output from the Neural Net is a special "no character" output which effectively gives you the character segmentation. You can distinguish "aa" from "a" because the former shows up as "(no)a(no)a(no)" whereas the latter is "(no)a(no)". You can read more about this in the Ocropus paper: http://www.helsinki.fi/~mpsilfve/ocr_course/materials/2008-breuel-ocropus-open-source.pdf http://www.helsinki.fi/~mpsilfve/ocr_course/materials/2008-b...
sherjilozair 12y ago
Slightly off-topic, but is anyone aware of an similarly capable library for hand-written text recognition, i.e. ICR?
- danvk 12y ago
  If you're able to provide enough training data, there's no reason Ocropus couldn't do this. If you're open to using a commercial OCR program, FineReader is excellent.
martingordon 12y ago
Thanks for this. I tried using Tesseract over the weekend to extract text from a game screenshot and had no luck. The documentation for Tesseract is rather opaque; maybe I'll have better luck with Ocropus.
- danvk 12y ago
  I wouldn't say that Ocropus is well-documented (this blog post was partially intended to address that). But it's at least written in easily hackable Python, whereas Tesseract is 30 year old C/C++.
- joaomsa 12y ago
  My main gripe with tesseract is how convoluted and lacking in documentation the training procedure is, which is critical to getting better results. I'll be sure to check out ocropus.
  - danvk 12y ago
    You'll enjoy my follow-up post then, which talks about training: http://www.danvk.org/2015/01/11/training-an-ocropus-ocr-model.html http://www.danvk.org/2015/01/11/training-an-ocropus-ocr-mode...
soperj 12y ago
Are there any OCR/ICR open source projects that are actively being worked on that anyone knows about?
- danvk 12y ago
  Ocropus is fairly actively developed. Lots of commits in 2015: https://github.com/tmbdev/ocropy/commits/master https://github.com/tmbdev/ocropy/commits/master

63 points by danvk 12y ago

I wonder if it's possible to remove the need for post-processing of the LSTM's output by integrating transcription into the neural network model directly.

danvk 12y ago
The first row of output from the Neural Net is a special "no character" output which effectively gives you the character segmentation. You can distinguish "aa" from "a" because the former shows up as "(no)a(no)a(no)" whereas the latter is "(no)a(no)". You can read more about this in the Ocropus paper: http://www.helsinki.fi/~mpsilfve/ocr_course/materials/2008-breuel-ocropus-open-source.pdf http://www.helsinki.fi/~mpsilfve/ocr_course/materials/2008-b...

sherjilozair 12y ago

Slightly off-topic, but is anyone aware of an similarly capable library for hand-written text recognition, i.e. ICR?

danvk 12y ago
If you're able to provide enough training data, there's no reason Ocropus couldn't do this. If you're open to using a commercial OCR program, FineReader is excellent.

martingordon 12y ago

Thanks for this. I tried using Tesseract over the weekend to extract text from a game screenshot and had no luck. The documentation for Tesseract is rather opaque; maybe I'll have better luck with Ocropus.

danvk 12y ago
I wouldn't say that Ocropus is well-documented (this blog post was partially intended to address that). But it's at least written in easily hackable Python, whereas Tesseract is 30 year old C/C++.
joaomsa 12y ago
My main gripe with tesseract is how convoluted and lacking in documentation the training procedure is, which is critical to getting better results. I'll be sure to check out ocropus.
- danvk 12y ago
  You'll enjoy my follow-up post then, which talks about training: http://www.danvk.org/2015/01/11/training-an-ocropus-ocr-model.html http://www.danvk.org/2015/01/11/training-an-ocropus-ocr-mode...

soperj 12y ago

Are there any OCR/ICR open source projects that are actively being worked on that anyone knows about?

danvk 12y ago
Ocropus is fairly actively developed. Lots of commits in 2015: https://github.com/tmbdev/ocropy/commits/master https://github.com/tmbdev/ocropy/commits/master