extracting text from png files

Linux for blind general discussion blinux-list at redhat.com
Tue Dec 18 18:48:19 UTC 2018

OK, this is a nit, but the O in OCR stands for "Optical," not "Ocular."

It's about the process based on vision, not on the organ that is
sensitive to light. Machines don't have eyes, biological beings have

Linux for blind general discussion writes:
> What you're looking for is Ocular Character Recognition or OCR for short.
> I've never managed to figure out its command line syntax, but I
> believe tesseract is considered the current standard option for Linux.
> There's also Cuneiform, which I have actually used with some success
> in the past, but I believe its either contrib or non-free under
> Debian, so you might need to enable extra repositories depending on
> how strict your distro is about sticking to FOSS principles.
> I will warn you, in my experience, OCR is as likely to produce
> gibberish as legible text. A scan of a page of prose type set in a
> standard font will probably OCR well, but the more mixed text is with
> graphics, the fancier the font, and the more complicated the page
> layout, the more likely errors are. I've tried OCR'ing scanlated
> manga(Japanese comics) in the past and have gotten results that
> included unpredictible patterns of letters and numbers misidentified
> as others(S and 5, P and D, I and 1, LI and U, B and g where just some
> of the common substitutions I encountered trying to fix the OCR'd
> text), characters my screenreader could'nt identify or identified as
> characters I'm unfamiliar, and even when the text was clear,
> paragraphs out of order wasn't uncommon.
> -- 
> Sincerely,
> Jeffery Wright
> Bachelor of Computer Science
> President Emeritus, Nu Nu Chapter, Phi Theta Kappa.
> _______________________________________________
> Blinux-list mailing list
> Blinux-list at redhat.com
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Janina Sajka

Linux Foundation Fellow
Executive Chair, Accessibility Workgroup:	http://a11y.org

The World Wide Web Consortium (W3C), Web Accessibility Initiative (WAI)
Chair, Accessible Platform Architectures	http://www.w3.org/wai/apa

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