[jira] [Commented] (TIKA-3258) Run OCR on PDFs with 'auto' mode as default in Tika 2.0.0

["Shmuel Krakower (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TIKA-3258?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17314454#comment-17314454 ] 

Shmuel Krakower commented on TIKA-3258:
---------------------------------------

Hi [~tallison]

This is my first comment in the TIKA project and hope that's the appropriate place. If not plz lmk of the right place.

I know this is already done but you mentioned earlier in this ticket the purpose here to have some discussion.

 

I was wondering regarding the point you mention in the ticket description:
{quote}
_option 2, which renders each page and then runs OCR on that composite image rather than running OCR on each inline image...so we'll only call tesseract once per page._
{quote}
 

I notice that when running with OCR_AND_TEXT_EXTRACTION mode (I assume the same goes for AUTO, in the mentioned cases) - the entire page is rendered and then OCRed but also each of the images is being OCRed.

If that's expected, I wonder why? (I was expecting that if a page is being rendered for OCR, there's no need for also OCRing the embedded images, but maybe there's a good reason for that)

 

> Run OCR on PDFs with 'auto' mode as default in Tika 2.0.0
> ---------------------------------------------------------
>
>                 Key: TIKA-3258
>                 URL: https://issues.apache.org/jira/browse/TIKA-3258
>             Project: Tika
>          Issue Type: Improvement
>            Reporter: Tim Allison
>            Assignee: Tim Allison
>            Priority: Major
>             Fix For: 2.0.0
>
>
> In Tika 1.x we currently have the fiddly mess that users have to configure OCR of PDFs...it doesn't just work out of the box.  We did this initially because of concerns (well, reality) of crazy resource consumption for some PDFs that can have thousands of images per page that are stitched together to make a reasonable composite.
> Since then, we've added option 2, which renders each page and then runs OCR on that composite image rather than running OCR on each inline image...so we'll only call tesseract once per page.  Second, we've added an 'auto' mode that runs OCR only on pages that didn't have much text extracted.  While there is plenty of room for improvement in the 'auto' heuristic, I think we should move to running OCR automatically on PDFs as default in 2.0.0. 
> Under this proposal, users will now have to disable OCR if they have tesseract installed but don't want to run it on PDFs.
> This will be a breaking change, and we'll make sure to document it early and often in the "Breaking Changes" sections of the readme.txt.



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