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Ask HN: Open source OCR library?

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Re: Ask HN: Open source OCR library?

#71

Post by antjanus »

rashfael wrote: post #64

(Disclaimer: I work for creatale GmbH) As you mentioned ocrad.js I assume you search for something in js/nodejs. Many others already recommended tesseract and OpenCV. We have built a library around tesseract for character recognition and OpenCV (and other libraries) for preprocessing, all for node.js/io.js: https://github.com/creatale/node-dv If you have to recognize forms or other structured images, we also created…

I can attest to this. I used Node-DV in a production environment and it's pretty damn amazing with all its built-in functionality.

There are options to adjust the image in various ways and once Tesseract runs, it's easy to get the result in various formats.

Re: Ask HN: Open source OCR library?

#72

Post by totalcookie »

loumf wrote: post #44
totalcookie wrote: post #39

Earlier quoted context omitted.

Finereader engine Abbyy for Linux looks fine, but I can't find price data, is it <10k/year? One time license?

Abbyy, and most good commercial OCR, charge a runtime royalty based on the number of cores you are deploying to. Depends on volume.

Can you point me to some prices, per core / core-year?

Re: Ask HN: Open source OCR library?

#73

Post by totalcookie »

zo1 wrote: post #69
loumf wrote: post #44

Earlier quoted context omitted.

Abbyy, and most good commercial OCR, charge a runtime royalty based on the number of cores you are deploying to. Depends on volume.

And they limit you to scanned pages per year on the corporate/server offerings. Doubly-so for all their dev/api license options. And the kicker: You can't buy those licenses from them directly. They put you in contact with some randome monopoly local distributor that usually has mandatory "training" charges. Messy, and I'm planning on staying away from that with a ten-foot pole.

If there is no opensource/free software with the same quality, what then? What are you using as an OCR server side system on Linux? I'm sure not good enough to write my own OCR better than Abbyy.

Re: Ask HN: Open source OCR library?

#75

Post by balakk »

bittersweet wrote: post #37

I was actually looking in to Tesseract yesterday, so this post coincides nicely. I have a hobby project where I scrape instagram photos, and I actually only want to end up with photos with actual people in them. There are a lot of images being posted with motivational texts etc that I want to automatically filter out. So far I've already built a binary that scans images and spits out the dominant color percentage, if…

dlib's face detection is the best of the open-source libs, in my experience.

http://blog.dlib.net/2014/02/dlib-186-released-make-your-own...

It's a brilliant piece of software for a number of things.

Re: Ask HN: Open source OCR library?

#76

Post by kefka »

NeutronBoy wrote: post #14
WalterGR wrote: post #11

Earlier quoted context omitted.

Tesseract does no layout analysis. So if the source image contains text columns or pull quotes or similar, the output text will just be each row of text, from the far left to the far right.

Could you add another layer on top (eg. image processing) to detect boundaries of blocks of content, and send each block to Tesseract in sequence?

Yeah, you could do that. And I wouldn't think it would be that hard either.

I'd make a cascade that detects all letters and numbers from major font sets. That shouldn't be too terribly difficult.

Now, use the cascade to scan the document. Now, convert the document to a list of all detected characters (we don't actually care what the chars are).

Once you have this, do best fit bounding boxes around the data. You'll have to figure out what distance you want to exclude from the bounding boxes.

Now what you should end up with are a few boxes indicating the regions of data on the document. Now, crop each of these regions of interest and feed them into Tesseract.

Re: Ask HN: Open source OCR library?

#77

Post by bouyoul420 »

riordan wrote: post #59
sandGorgon wrote: post #5

http://www.danvk.org/2015/01/11/training-an-ocropus-ocr-mode...

Yep. Back when I was at NYPL Labs[0], we developed a bit of an obsession with OCR. It turns out that so much of it depends on the context of the documents, original scan quality (unpaper and deskewing be damned), typography, how much handwriting you're willing to suffer (can someone please pick up the work of applying Convnets to large handwriting corpora that aren't just MNIST?). A lot of this comes down to how much…

Great list of links. You have done the research! Personally, I have used ocropy to great effect. Right now, I am moving beyond forms at work and researching cartographic map vectorization using deep learning techniques. There is little science papers on the subject however. Have you done any research on that by any chance?

Re: Ask HN: Open source OCR library?

#78

Post by loisaidasam »

automentum wrote: post #19

Any references on OCR to extract MICR (font E13B) for desktop as well as Android?

Dunno about desktop, but as far as Android is concerned, tess-two is a fork of Tesseract tools for Android: https://github.com/rmtheis/tess-two

This dude did a pretty nice writeup on getting it going: http://gaut.am/making-an-ocr-android-app-using-tesseract/

Re: Ask HN: Open source OCR library?

#79

Post by loumf »

totalcookie wrote: post #72
loumf wrote: post #44

Earlier quoted context omitted.

Abbyy, and most good commercial OCR, charge a runtime royalty based on the number of cores you are deploying to. Depends on volume.

Can you point me to some prices, per core / core-year?

I believe you need to call them.

Re: Ask HN: Open source OCR library?

#80

Post by zaphar »

I used the go wrappers for tesseract[0] in my full text search indexer for disks[1] and it worked great. No issues it handled pretty much anything I threw at it.

With the caveat that none of the stuff was handwritten.

[0] http://godoc.org/gopkg.in/GeertJohan/go.tesseract.v1 [1] https://bitbucket.org/zaphar/goin/

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