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OCR is my current approach. I am not really happy with it. The quality of OCRing leaves much to be desired, probably due to the documents themselves being hap

OCR is my current approach. I am not really happy with it. The quality of OCRing leaves much to be desired, probably due to the documents themselves being haphazardly handled by the court personnel. OCR itself is a pretty CPU intensive activity and takes a significant time to complete for many documents. Thus, I was looking for a more advanced approach.

jononor 10y ago
What do you want to recognize? OCR is a better understood problem than a general neural net, so I think it's likely easier to improve its quality that to superseded the quality with image-based recognition.
- starik36 10y ago
  Ideally, I would like to get all the information from the page. Phone numbers, who is suing whom, case caption, etc... With OCR, you get bits and pieces of information, but because I don't know what the type of the document is, it is difficult to determine where, structurally speaking, this information resides on a page. If I could use AI to determine the type of the doc, I would know the structure of the document and I could then use OCR to pinpoint specific information on the page. Most court documents are created from templates.
  - jononor 10y ago
    If your OCR is unable to recognize the characters on a full page, I don't think it when scanning a region either? Unless using full resolution of a full image is somehow too much for the algorithm in use. But then I'd just subdivide the entire image into regions, and scan them all independently. This is also a trivially parallelizable task, so you can throw many servers at it, if the time to get results is an issue.
barrkel 10y ago
I think you'd have a better time doing your OCR on AWS - spread the CPU intensive activity across multiple machines. Even if the resulting text has errors, if you're doing further document classification, it would be better to do it on the text including the errors, than on the original images.
perfmode 10y ago
You don't need perfect character recognition. It's just gotta be good enough. The way you determine good enough is by completing the pipeline and measuring the result.
johncip 10y ago
> OCR itself is a pretty CPU intensive activity and takes a significant time to complete for many documents. Leaving the quality part aside -- this job itself is easy to parallelize in that you can split it up by document or by page. Open option is to run each job in Lambda asynchronously, with the input being a URL to the page or the full document, and have the job call back to you with the text of the page (or put it on S3 as a text file, or add it to a message queue, or whatever works). Regarding splitting: we've been using a python wrapper + pdfium for splitting PDFs into page images on Lambda, with excellent results. To make the Lambda function, you'll either have to build e.g. Tesseract such that it fits into a 50MB zip, or download it while the Lambda function executes. LambCI has a set of docker containers that they've made for simulating lambda, and the "lambda:build" container makes building things easy and repeatable: https://github.com/lambci/docker-lambda https://github.com/lambci/docker-lambda. In a pinch, you can build on an Amazon Linux EC2 instance and it should work on Lambda, but you will have to be more careful about dynamic linking. As another option: I'm not sure if it's been mentioned, but you can also try a ready-made OCR service before packaging up Tesseract, like this one: https://algorithmia.com/algorithms/ocr/SmartOCR https://algorithmia.com/algorithms/ocr/SmartOCR. So anyway, the performance part has good solutions, at least. For fixing the accuracy: I know next to nothing about approximate string matching, but perhaps it would then be possible to do a fuzzy search over the text using something similar a Levenshtein automaton: https://en.wikipedia.org/wiki/Levenshtein_automaton https://en.wikipedia.org/wiki/Levenshtein_automaton. You may also want to take a look at this: https://en.wikipedia.org/wiki/Bag-of-words_model https://en.wikipedia.org/wiki/Bag-of-words_model More broadly, I'm sure that there are text-based document classification methods that are robust against sloppy OCR. It may just take some research on the main approaches people take to document classification -- it's not my area, but my understanding is that this is typically approached with statistical methods. Otherwise your spam filter would get defeated by typos.

jononor 10y ago

What do you want to recognize? OCR is a better understood problem than a general neural net, so I think it's likely easier to improve its quality that to superseded the quality with image-based recognition.

starik36 10y ago
Ideally, I would like to get all the information from the page. Phone numbers, who is suing whom, case caption, etc... With OCR, you get bits and pieces of information, but because I don't know what the type of the document is, it is difficult to determine where, structurally speaking, this information resides on a page. If I could use AI to determine the type of the doc, I would know the structure of the document and I could then use OCR to pinpoint specific information on the page. Most court documents are created from templates.
- jononor 10y ago
  If your OCR is unable to recognize the characters on a full page, I don't think it when scanning a region either? Unless using full resolution of a full image is somehow too much for the algorithm in use. But then I'd just subdivide the entire image into regions, and scan them all independently. This is also a trivially parallelizable task, so you can throw many servers at it, if the time to get results is an issue.

barrkel 10y ago

I think you'd have a better time doing your OCR on AWS - spread the CPU intensive activity across multiple machines. Even if the resulting text has errors, if you're doing further document classification, it would be better to do it on the text including the errors, than on the original images.

perfmode 10y ago

You don't need perfect character recognition. It's just gotta be good enough. The way you determine good enough is by completing the pipeline and measuring the result.

johncip 10y ago

> OCR itself is a pretty CPU intensive activity and takes a significant time to complete for many documents. Leaving the quality part aside -- this job itself is easy to parallelize in that you can split it up by document or by page. Open option is to run each job in Lambda asynchronously, with the input being a URL to the page or the full document, and have the job call back to you with the text of the page (or put it on S3 as a text file, or add it to a message queue, or whatever works). Regarding splitting: we've been using a python wrapper + pdfium for splitting PDFs into page images on Lambda, with excellent results. To make the Lambda function, you'll either have to build e.g. Tesseract such that it fits into a 50MB zip, or download it while the Lambda function executes. LambCI has a set of docker containers that they've made for simulating lambda, and the "lambda:build" container makes building things easy and repeatable: https://github.com/lambci/docker-lambda https://github.com/lambci/docker-lambda. In a pinch, you can build on an Amazon Linux EC2 instance and it should work on Lambda, but you will have to be more careful about dynamic linking. As another option: I'm not sure if it's been mentioned, but you can also try a ready-made OCR service before packaging up Tesseract, like this one: https://algorithmia.com/algorithms/ocr/SmartOCR https://algorithmia.com/algorithms/ocr/SmartOCR. So anyway, the performance part has good solutions, at least. For fixing the accuracy: I know next to nothing about approximate string matching, but perhaps it would then be possible to do a fuzzy search over the text using something similar a Levenshtein automaton: https://en.wikipedia.org/wiki/Levenshtein_automaton https://en.wikipedia.org/wiki/Levenshtein_automaton. You may also want to take a look at this: https://en.wikipedia.org/wiki/Bag-of-words_model https://en.wikipedia.org/wiki/Bag-of-words_model More broadly, I'm sure that there are text-based document classification methods that are robust against sloppy OCR. It may just take some research on the main approaches people take to document classification -- it's not my area, but my understanding is that this is typically approached with statistical methods. Otherwise your spam filter would get defeated by typos.