Open Source OCR in JavaScript • Hacker News Board

Re: Open Source OCR in JavaScript

#11

Post by SIGALRM » Wed, Jul 30, 2014, 2:06 PM UTC

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.

Re: Open Source OCR in JavaScript

#12

Post by gry » Wed, Jul 30, 2014, 2:45 PM UTC

mrfusion wrote: post #8

Would this be an easy way to get OCR into an iPhone app with phone gap? Could it operate on a live video feed?

It might be easy, but until iOS 8 is released, non-Safari JS still takes a performance hit. [1] You may want to take a look at the Tesseract library and Objective-C wrapper. [2]

[1] http://9to5mac.com/2014/06/03/ios-8-webkit-changes-finally-a... [2] https://github.com/ldiqual/tesseract-ios

edit: Looking closer at this lib, impressive. Might give it a go.

Re: Open Source OCR in JavaScript

#13

Post by systematical » Wed, Jul 30, 2014, 2:46 PM UTC

Hand writing my name Chris was difficult for it to pick up. It kept thinking my "C" was an "L" and putting spaces in between letters. Also determined my "S" was an underscore. Still pretty cool. Thanks!

Re: Open Source OCR in JavaScript

#14

Post by alistairjcbrown » Wed, Jul 30, 2014, 3:07 PM UTC

systematical wrote: post #13

Hand writing my name Chris was difficult for it to pick up. It kept thinking my "C" was an "L" and putting spaces in between letters. Also determined my "S" was an underscore. Still pretty cool. Thanks!

Looks like underscore character ("_") is used when the letter can't be determined - so in fact it had no idea what your "S" was ^_^

Re: Open Source OCR in JavaScript

#15

Post by alistairjcbrown » Wed, Jul 30, 2014, 3:23 PM UTC

Interesting - I've had the Project Naptha (http://projectnaptha.com/) Chrome extension installed without really looking under the hood. Turns out it has Ocrad.js and Tesseract as two engine options - it uses them to automaticaly convert images on the page to selectable text.

Re: Open Source OCR in JavaScript

#16

Post by bignis » Wed, Jul 30, 2014, 3:51 PM UTC

It demos well, but then I tried a simple test - a photograph of some text (http://imgur.com/TCnGlZG), Ocrad.js utterly failed at it, almost all letters were incorrect.

Re: Open Source OCR in JavaScript

#17

Post by jahewson » Wed, Jul 30, 2014, 4:05 PM UTC

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?

Ocrad is not very powerful, it uses hand-written recognisers (one per character) to identify the shapes of the characters. Compare this with more modern libraries such as Tesseract which use neural networks and OCRopus which adds language modelling.

Re: Open Source OCR in JavaScript

#18

Post by cheshire137 » Wed, Jul 30, 2014, 4:09 PM UTC

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.

Re: Open Source OCR in JavaScript

#19

Post by fnordsensei » Wed, Jul 30, 2014, 4:37 PM UTC

Love the idea of it. However, I threw some random Swedish at it, and it didn't fare too well. http://imgur.com/nZLtoj5 Kudos for the effort though!

Re: Open Source OCR in JavaScript

#20

Post by paulirish » Wed, Jul 30, 2014, 4:57 PM UTC

alistairjcbrown wrote: post #15

Interesting - I've had the Project Naptha ( http://projectnaptha.com/ ) Chrome extension installed without really looking under the hood. Turns out it has Ocrad.js and Tesseract as two engine options - it uses them to automaticaly convert images on the page to selectable text.

Yup! And Naptha and Ocrad.js are both authored by antimatter15.