tesseract-ocr / tesstrain

Train Tesseract LSTM with make
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Ground truth: spaces before and after text? #335

Open jbarth-ubhd opened 1 year ago

jbarth-ubhd commented 1 year ago

I've created *.exp0.gt.txt as a base for manual ground truth creation using Shreeshrii's shell script and the files contain a space before and after the text (no newlines etc). Example:

01127778-001.exp0.gt.txt: " Verfahrenstechnik / -70 B 2813 "
01127778-002.exp0.gt.txt: " Verfahrenstechnik, Forschung und Lehre, (Zsgest. Ue "
01127778-003.exp0.gt.txt: " verf. von Kurt Schiefer und Kurt Boekmer,) "
01127778-004.exp0.gt.txt: " Düsseldorf: Verfahrenstechnische Ges, im Verein Deut- ! "
01127778-005.exp0.gt.txt: " scher Ingenieure 1967. 185 S, 8° "
01127778-006.exp0.gt.txt: " Frühere Ausg. 3. u.d.T.: Verfahrenstechnik im In- und "
01127778-007.exp0.gt.txt: " Ausland. "

... but The-Hallucination-Effect states »Example 2: Your training text frequently includes a Space at the beginning of your sentences or at the end. Might result in slow training, non-convergence & even model corruption.«

My Question: Spaces or not?

The 1 line images are very tight, no blank space before/after; example: grafik

jbarth-ubhd commented 1 year ago

ok, ocrd-testset.zip *.gt.txt contain no spaces before/after, but \n

vishakraj25 commented 1 year ago

ok, ocrd-testset.zip *.gt.txt contain no spaces before/after, but \n

@jbarth-ubhd, I see there is no space or no new line at the end of the *.gt.txt

jbarth-ubhd commented 1 year ago

I'll see newlines (4th line below):

jb@xxx:~/Downloads/ocrd-testset> cat *.gt.txt|od -c|head
0000000   i   c   h       d   e   n   k   e   .       A   b   e   r    
0000020   w   a   s       d   i   e     305 277   e   l   i   g   e    
0000040   F   r   a   u       G   e   h   e   i   m   r 303 244   t   h
0000060   i   n  \n 342 200 236   D   a   s       k   a   n   n       i
0000100   c   h       n   i   c   h   t   ,       c   '   e   s   t    
stweil commented 1 year ago

Ground truth line text must not have spaces before or after the text. It may end with a linefeed (which gets added automatically by many editors).

jbarth-ubhd commented 1 year ago

Just tried it again with https://github.com/tesseract-ocr/tesstrain/issues/7 and https://github.com/ocropus/hocr-tools/blob/master/hocr-extract-images , the generated .exp0.gt.txt files contain spaces before & after:

308-119.exp0.gt.txt: " | == zz NN NN ANNE NZZ SE anli : "
308-120.exp0.gt.txt: " <C3><BC>ber 1 BONS DD DD SS EN U = NS utfer]pras "
308-121.exp0.gt.txt: " Datei ihrem unfeligen zZ <E2><80><94> SS AN . LEE KA 5 XS Ode bot. "
308-122.exp0.gt.txt: " N ein SH 7 DD SS 7 ea san Zn EFF LEE Z<E2><80><94>_-- BEN UNE x "
stale[bot] commented 1 year ago

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

jbarth-ubhd commented 1 year ago

bump

stweil commented 1 year ago

Just tried it again with #7 and https://github.com/ocropus/hocr-tools/blob/master/hocr-extract-images , the generated .exp0.gt.txt files contain spaces before & after

Then I assume that the original data (hOCR) already contains such spaces. Do you have a link to an example?

jbarth-ubhd commented 1 year ago

The .hocr does not contain spaces: <span ...>abcdefg</span>, but the .exp0.gt.txt does so.

See https://digi.ub.uni-heidelberg.de/diglitData/v/tesstrain-issue-335.zip for a complete test environment; main script is Shreeshrii-script.

jbollacke commented 8 months ago

The spaces before and after the line occur, if your hocr file is indented.

hocr-extract-images uses regex to replace one (or more) whitespace characters with one space. see line 20

i am not sure if they had indentation in mind, though.