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Open Source OCR in JavaScript

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Re: Open Source OCR in JavaScript

#21

Post by iLoch »

SIGALRM wrote: post #11
jfoster wrote: post #9

I am a bit surprised at how low the accuracy seems to be. Does anyone know if this is typical just of OCR done in JS, or OCR in general? I am aware that at least one or two implementations are extremely good (eg. Google ones) but are those complete outliers?

in my humble experience using OCR programs, there is always a considerable amount inaccuracy. no matter what font I use or font size, I always either end up proof reading the scanned document or just typing it by hand. the letter "O" is almost always translated by the OCR as a "0" or a zero is translated as an "O". it can be pretty frustrating.

I wish there was a library that allowed you to input expected data (ex: we expect to see zeros 20% more often then the letter O), then the interpreter could compare against that fact and determine the likelihood of it being each letter. As it stands for most libraries that I'm aware of, you just have to get the data and run your own tests to see whether it should be an O or a zero.

Re: Open Source OCR in JavaScript

#22

Post by Zergy »

SIGALRM wrote: post #11
jfoster wrote: post #9

I am a bit surprised at how low the accuracy seems to be. Does anyone know if this is typical just of OCR done in JS, or OCR in general? I am aware that at least one or two implementations are extremely good (eg. Google ones) but are those complete outliers?

in my humble experience using OCR programs, there is always a considerable amount inaccuracy. no matter what font I use or font size, I always either end up proof reading the scanned document or just typing it by hand. the letter "O" is almost always translated by the OCR as a "0" or a zero is translated as an "O". it can be pretty frustrating.

I used the ABBYY orc engine to digitize printed documents (idk why they couldn't just keep around the file used to print) and it was quite accurate. At worst one out of a couple hundred would have enough issues where readability was an issue.

Re: Open Source OCR in JavaScript

#23

Post by gfosco »

Zergy wrote: post #22
SIGALRM wrote: post #11

Earlier quoted context omitted.

in my humble experience using OCR programs, there is always a considerable amount inaccuracy. no matter what font I use or font size, I always either end up proof reading the scanned document or just typing it by hand. the letter "O" is almost always translated by the OCR as a "0" or a zero is translated as an "O". it can be pretty frustrating.

I used the ABBYY orc engine to digitize printed documents (idk why they couldn't just keep around the file used to print) and it was quite accurate. At worst one out of a couple hundred would have enough issues where readability was an issue.

Similar experience here, when building a mobile app that did OCR + translations.. As long as the source image was in decent shape, ABBYY did very well. It's also incredibly expensive.

Re: Open Source OCR in JavaScript

#24

Post by azakai »

cheshire137 wrote: post #18

I kept giggling at its poor recognition. It's comically bad, but I think it's a step in the right direction. It was very fast at incorrectly identifying letters. If only it were very fast and mostly correct.

It is good at recognizing machine-generated text - hit the blue arrow - and not that good at human-scribbled text with a mouse, I find.

I assume you were testing hand-written text?

Re: Open Source OCR in JavaScript

#25

Post by 67726e »

jfoster wrote: post #9

I am a bit surprised at how low the accuracy seems to be. Does anyone know if this is typical just of OCR done in JS, or OCR in general? I am aware that at least one or two implementations are extremely good (eg. Google ones) but are those complete outliers?

I work at a publisher with millions of digitized historical books that we OCR and Abbyy is what we use. Nothing else came close to Abbyy. It is incredibly good, but incredibly expensive.

Re: Open Source OCR in JavaScript

#26

Post by darklajid »

jfoster wrote: post #9

I am a bit surprised at how low the accuracy seems to be. Does anyone know if this is typical just of OCR done in JS, or OCR in general? I am aware that at least one or two implementations are extremely good (eg. Google ones) but are those complete outliers?

That is specific for this implementation. Note that cursive/handwritten text will continue to be an issue, but machine printed is pretty solid and especially easy if you can narrow down the scope of the expected result (somewhere in this thread someone wonders of it would be possible to prefer 0 to o etc - sure). Note that

a) it's not possible to consistently reach 100% (and depending on the source material and circumstances far less) recognition (have to educate customers about that..)

b) errors are a tradeoff between 'dunno' and 'might be a zero' aka miss vs. false positive. Benchmarks/evaluations usually consider the latter far worse, prefering jf?oster to jf0ster by a long shot. So that's what you'll try to archive.

Source: Approaching ten years (yeah..) in a company that sells OCR solutions and more, integrating Abby, Oce and another half a dozen commercial engines.

Re: Open Source OCR in JavaScript

#28

Post by xhrpost »

darklajid wrote: post #26
jfoster wrote: post #9

I am a bit surprised at how low the accuracy seems to be. Does anyone know if this is typical just of OCR done in JS, or OCR in general? I am aware that at least one or two implementations are extremely good (eg. Google ones) but are those complete outliers?

That is specific for this implementation. Note that cursive/handwritten text will continue to be an issue, but machine printed is pretty solid and especially easy if you can narrow down the scope of the expected result (somewhere in this thread someone wonders of it would be possible to prefer 0 to o etc - sure). Note that a) it's not possible to consistently reach 100% (and depending on the source material and circu…

> machine printed is pretty solid

You mean OCR in general or ocradJS? I tried cropping a picture down in the later and I can't get it to come even close: http://imgur.com/cesg0IE

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