Empty result with images taken as marginally low resolution - Nepali

[Nirajan Pant]

Tesseract 4.0 is not working with the image provided here. This is a page from Nepali novel. The resolution is slightly low but not too much. The OCR result only few word or in other pages it returns empty result. 

[ShreeDevi Kumar]

Works fine for me. What traineddata and options did you use?

Attaching the output from the following, I did not change dpi of image.

#!/bin/bash

img_files=$(ls ./nepali*.png)

for img_file in ${img_files}; do

  echo "****************************" ${img_file} oem 1"**********************************"

 time tesseract --tessdata-dir /mnt/c/Users/User/shree/tessdata_best/   ${img_file} ${img_file%.*}-Devanagari-best  --oem 1 --psm 6 -l Devanagari 

 time tesseract --tessdata-dir /mnt/c/Users/User/shree/tessdata_fast/   ${img_file} ${img_file%.*}-Devanagari-fast  --oem 1 --psm 6 -l Devanagari 

 time tesseract --tessdata-dir /mnt/c/Users/User/shree/tessdata/   ${img_file} ${img_file%.*}-nep  --oem 1 --psm 6 -l nep 

done

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

On Thu, Jan 11, 2018 at 9:44 PM, Nirajan Pant <nira...@gmail.com> wrote:

Tesseract 4.0 is not working with the image provided here. This is a page from Nepali novel. The resolution is slightly low but not too much. The OCR result only few word or in other pages it returns empty result. 

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[Nirajan Pant]

I was using Automatic page segmentation mode. Why automatic mode does not work? Here is sample command

tesseract.exe "E:\Projects\NeOCR_rev1\Text Image Segmenter\bin\Debug\tesseract\tmp_20180111201447661_page-6.png" out --tessdata-dir "E:\Projects\NeOCR_rev1\Text Image Segmenter\bin\Debug\tesseract\tessdata" -l nep --psm 1 --oem 1

On Friday, 12 January 2018 09:59:32 UTC+5:45, shree wrote:

Works fine for me. What traineddata and options did you use?

Attaching the output from the following, I did not change dpi of image.

#!/bin/bash

img_files=$(ls ./nepali*.png)

for img_file in ${img_files}; do

  echo "****************************" ${img_file} oem 1"**********************************"

 time tesseract --tessdata-dir /mnt/c/Users/User/shree/tessdata_best/   ${img_file} ${img_file%.*}-Devanagari-best  --oem 1 --psm 6 -l Devanagari 

 time tesseract --tessdata-dir /mnt/c/Users/User/shree/tessdata_fast/   ${img_file} ${img_file%.*}-Devanagari-fast  --oem 1 --psm 6 -l Devanagari 

 time tesseract --tessdata-dir /mnt/c/Users/User/shree/tessdata/   ${img_file} ${img_file%.*}-nep  --oem 1 --psm 6 -l nep 

done

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

On Thu, Jan 11, 2018 at 9:44 PM, Nirajan Pant <nira...@gmail.com> wrote:

Tesseract 4.0 is not working with the image provided here. This is a page from Nepali novel. The resolution is slightly low but not too much. The OCR result only few word or in other pages it returns empty result. 

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[ShreeDevi Kumar]

psm 1 is 1 Automatic page segmentation with OSD.

psm 3 is 3 Fully automatic page segmentation, but no OSD. (Default)

see https://github.com/tesseract-ocr/tesseract/wiki/Command-Line-Usage

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

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[Nirajan Pant]

--psm 3 also not working. 

[ShreeDevi Kumar]

Please file an issue with full details.

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

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[ShreeDevi Kumar]

It seems some bug has crept in the processing of diff psm modes. OCR worked only for psm 4 and 6

**************************** ./nepali.png oem 1**********************************

psm 1

Tesseract Open Source OCR Engine v4.00.00alpha with Leptonica

Warning. Invalid resolution 0 dpi. Using 70 instead.

Estimating resolution as 434

OSD: Weak margin (6.54) for 34 blob text block, but using orientation anyway: 0

Empty page!!

Estimating resolution as 434

OSD: Weak margin (6.54) for 34 blob text block, but using orientation anyway: 0

Empty page!!

real    0m3.201s

user    0m2.250s

sys     0m0.641s

psm 2

Warning. Invalid resolution 0 dpi. Using 70 instead.

Estimating resolution as 434

Empty page!!

real    0m1.860s

user    0m1.094s

sys     0m0.516s

psm 3

Tesseract Open Source OCR Engine v4.00.00alpha with Leptonica

Warning. Invalid resolution 0 dpi. Using 70 instead.

Estimating resolution as 434

Empty page!!

Estimating resolution as 434

Empty page!!

real    0m2.086s

user    0m1.375s

sys     0m0.484s

psm 4

Tesseract Open Source OCR Engine v4.00.00alpha with Leptonica

Warning. Invalid resolution 0 dpi. Using 70 instead.

Estimating resolution as 434

real    0m7.769s

user    0m7.016s

sys     0m0.453s

psm 5

Tesseract Open Source OCR Engine v4.00.00alpha with Leptonica

Warning. Invalid resolution 0 dpi. Using 70 instead.

real    0m4.139s

user    0m3.359s

sys     0m0.484s

psm 6

Tesseract Open Source OCR Engine v4.00.00alpha with Leptonica

Warning. Invalid resolution 0 dpi. Using 70 instead.

real    0m7.727s

user    0m6.844s

sys     0m0.516s

[ShreeDevi Kumar]

Niranjan,

Please check with 'best' traineddata for nep. That seemed to work.

[Nirajan Pant]

Thank you Shree.