use multi threads in tesseract

[nick]

hi 

I want to run tesseract on cpu with 20 cores. but tesseract uses a few core when ocr a page !!!

how could i change the setting and force tesseract use all 20 cores ?!

thanks

[nick]

I found OMP_THREAD_LIMIT but i don't know to change it to 20 ?!

[Jakob Salomonsson]

Hello, 

Im having roughly the same problem, but related to pytesseract (maybe the same answer can be applied to both of them). 

I have tried several things, such as stating OMP_THREAD_LIMIT=4, for example, when calling the pytesseract function or adding "OMP_THREAD_LIMIT 4" in one or several of the config files. 

But still, no changes. Maybe Im just stating or adding in a wrong manner. 

Anyone knows how to help us advance in this? It would be of great help. 

[ShreeDevi Kumar]

Please see https://github.com/tesseract-ocr/tesseract/wiki/FAQ#can-i-increase-speed-of-ocr

Set the maximum number of threads using the environment variable OMP_THREAD_LIMIT.

ShreeDevi
____________________________________________________________
भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com

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[ShreeDevi Kumar]

Also see https://github.com/tesseract-ocr/tesseract/issues/1317

ShreeDevi
____________________________________________________________
भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com

[Jakob Salomonsson]

Thank you for your responses ShreeDevi. 

I have read the documentation you are referring to, but still I can't manage to get my head around on how, and where, to set this variable. A concrete example would be highly appreciated. 

Jakob

Den mån 28 maj 2018 kl 11:19 skrev ShreeDevi Kumar <shree...@gmail.com>:

Also see https://github.com/tesseract-ocr/tesseract/issues/1317

ShreeDevi
____________________________________________________________
भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com

On Mon, May 28, 2018 at 2:45 PM, ShreeDevi Kumar <shree...@gmail.com> wrote:

Please see https://github.com/tesseract-ocr/tesseract/wiki/FAQ#can-i-increase-speed-of-ocr

Set the maximum number of threads using the environment variable OMP_THREAD_LIMIT.

ShreeDevi
____________________________________________________________
भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com

On Mon, May 28, 2018 at 2:35 PM, Jakob Salomonsson <jakob.sa...@gmail.com> wrote:

Hello, 

Im having roughly the same problem, but related to pytesseract (maybe the same answer can be applied to both of them). 

I have tried several things, such as stating OMP_THREAD_LIMIT=4, for example, when calling the pytesseract function or adding "OMP_THREAD_LIMIT 4" in one or several of the config files. 

But still, no changes. Maybe Im just stating or adding in a wrong manner. 

Anyone knows how to help us advance in this? It would be of great help. 

Den måndag 28 maj 2018 kl. 09:27:00 UTC+2 skrev nick:

I found OMP_THREAD_LIMIT but i don't know to change it to 20 ?!

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[nick]

how  and where we could change this variable ? 

[Jakob Salomonsson]

Calling the help function in python through help(pytesseract.pytesseract) yields this result, among others:

DATA

    OMP_NUM_THREADS = 3

    OMP_THREAD_LIMIT = 3

    RGB_MODE = 'RGB'

    __warningregistry__ = {'version': 332, ('unclosed file <_io.BufferedWr...

    numpy_installed = True

    tesseract_cmd = '/anaconda3/envs/Work/bin/tesseract'

Im specifying tesseract_cmd (through:  pytesseract.pytesseract.tesseract_cmd = "/anaconda3/envs/Work/bin/tesseract") and it works as intended. 

But when I try to do the same with OMP_NUM_THREADS or OMP_THREAD_LIMIT (through: pytesseract.pytesseract.OMP_NUM_THREADS = 3 or pytesseract.pytesseract.OMP_THREAD_LIMIT = 3) no multi threading is happening. 

Den mån 28 maj 2018 kl 12:11 skrev nick <wcd...@gmail.com>:

how  and where we could change this variable ? 

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[nick]

hi 
I don't know , which file should change for OMP_NUM_THREADS ? or wihch command should test ?

[Jakob Salomonsson]

After speaking to one of the tesseract contributors:

import os

os.environ['OMP_THREAD_LIMIT'] = '2'

Should do the job, as OMP_NUM_THREADS is an environment variable. However, the speed difference is very small. It might be better to process several images in parallell rather than to process one as fast as possible. 

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[ShreeDevi Kumar]

Thank you for the info.

The following link also has helpful info.

https://www.ibm.com/support/knowledgecenter/SSGH2K_13.1.2/com.ibm.xlc131.aix.doc/compiler_ref/omp_thread_limit.html

ShreeDevi
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भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com

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[cosmin....@gmail.com]

I got the best results by using it in combination with GNU's parallel.

export OMP_THREAD_LIMIT=1

ls -U | parallel 'tesseract -l <lang> ./{} ./../extraction/{}'