<s>
Tesseract	B-Language
is	O
an	O
optical	B-Application
character	I-Application
recognition	I-Application
engine	O
for	O
various	O
operating	O
systems	O
.	O
</s>
<s>
It	O
is	O
free	B-Application
software	I-Application
,	O
released	O
under	O
the	O
Apache	B-Application
License	I-Application
.	O
</s>
<s>
Originally	O
developed	O
by	O
Hewlett-Packard	O
as	O
proprietary	O
software	O
in	O
the	O
1980s	O
,	O
it	O
was	O
released	O
as	O
open	O
source	O
in	O
2005	O
and	O
development	O
has	O
been	O
sponsored	O
by	O
Google	B-Application
since	O
2006	O
.	O
</s>
<s>
In	O
2006	O
,	O
Tesseract	B-Language
was	O
considered	O
one	O
of	O
the	O
most	O
accurate	O
open-source	O
OCR	O
engines	O
available	O
.	O
</s>
<s>
The	O
Tesseract	B-Language
engine	O
was	O
originally	O
developed	O
as	O
proprietary	O
software	O
at	O
Hewlett	O
Packard	O
labs	O
in	O
Bristol	O
,	O
England	O
and	O
Greeley	O
,	O
Colorado	O
between	O
1985	O
and	O
1994	O
,	O
with	O
more	O
changes	O
made	O
in	O
1996	O
to	O
port	O
to	O
Windows	B-Application
,	O
and	O
some	O
migration	O
from	O
C	B-Language
to	O
C++	B-Language
in	O
1998	O
.	O
</s>
<s>
A	O
lot	O
of	O
the	O
code	O
was	O
written	O
in	O
C	B-Language
,	O
and	O
then	O
some	O
more	O
was	O
written	O
in	O
C++	B-Language
.	O
</s>
<s>
Since	O
then	O
,	O
all	O
the	O
code	O
has	O
been	O
converted	O
to	O
at	O
least	O
compile	O
with	O
a	O
C++	B-Language
compiler	O
.	O
</s>
<s>
Tesseract	B-Language
development	O
has	O
been	O
sponsored	O
by	O
Google	B-Application
since	O
2006	O
.	O
</s>
<s>
Version	O
4	O
adds	O
LSTM	B-Algorithm
based	O
OCR	O
engine	O
and	O
models	O
for	O
many	O
additional	O
languages	O
and	O
scripts	O
,	O
bringing	O
the	O
total	O
to	O
116	O
languages	O
.	O
</s>
<s>
Tesseract	B-Language
was	O
in	O
the	O
top	O
three	O
OCR	O
engines	O
in	O
terms	O
of	O
character	O
accuracy	O
in	O
1995	O
.	O
</s>
<s>
It	O
is	O
available	O
for	O
Linux	B-Application
,	O
Windows	B-Application
and	O
Mac	B-Operating_System
OS	I-Operating_System
X	I-Operating_System
.	O
</s>
<s>
However	O
,	O
due	O
to	O
limited	O
resources	O
it	O
is	O
only	O
rigorously	O
tested	O
by	O
developers	O
under	O
Windows	B-Application
and	O
Ubuntu	B-Operating_System
.	O
</s>
<s>
Tesseract	B-Language
up	O
to	O
and	O
including	O
version	O
2	O
could	O
only	O
accept	O
TIFF	O
images	O
of	O
simple	O
one-column	O
text	O
as	O
inputs	O
.	O
</s>
<s>
Since	O
version	O
3.00	O
Tesseract	B-Language
has	O
supported	O
output	O
text	O
formatting	O
,	O
hOCR	B-General_Concept
positional	O
information	O
and	O
page-layout	O
analysis	O
.	O
</s>
<s>
Tesseract	B-Language
can	O
detect	O
whether	O
text	O
is	O
monospaced	O
or	O
proportionally	O
spaced	O
.	O
</s>
<s>
The	O
initial	O
versions	O
of	O
Tesseract	B-Language
could	O
only	O
recognize	O
English-language	O
text	O
.	O
</s>
<s>
Tesseract	B-Language
v2	O
added	O
six	O
additional	O
Western	O
languages	O
(	O
French	O
,	O
Italian	O
,	O
German	O
,	O
Spanish	O
,	O
Brazilian	O
Portuguese	O
,	O
Dutch	O
)	O
.	O
</s>
<s>
In	O
addition	O
,	O
Tesseract	B-Language
can	O
be	O
trained	O
to	O
work	O
in	O
other	O
languages	O
.	O
</s>
<s>
Tesseract	B-Language
can	O
process	O
right-to-left	O
text	O
such	O
as	O
Arabic	O
or	O
Hebrew	O
,	O
many	O
Indic	O
scripts	O
as	O
well	O
as	O
CJK	O
quite	O
well	O
.	O
</s>
<s>
Accuracy	O
rates	O
are	O
shown	O
in	O
this	O
presentation	O
for	O
Tesseract	B-Language
tutorial	O
at	O
DAS	O
2016	O
,	O
Santorini	O
by	O
Ray	O
Smith	O
.	O
</s>
<s>
Tesseract	B-Language
is	O
suitable	O
for	O
use	O
as	O
a	O
backend	O
and	O
can	O
be	O
used	O
for	O
more	O
complicated	O
OCR	O
tasks	O
including	O
layout	O
analysis	O
by	O
using	O
a	O
frontend	O
such	O
as	O
OCRopus	B-Language
.	O
</s>
<s>
Tesseract	B-Language
's	O
output	O
will	O
have	O
very	O
poor	O
quality	O
if	O
the	O
input	O
images	O
are	O
not	O
preprocessed	O
to	O
suit	O
it	O
:	O
Images	O
(	O
especially	O
screenshots	B-Application
)	O
must	O
be	O
scaled	B-Algorithm
up	O
such	O
that	O
the	O
text	O
x-height	O
is	O
at	O
least	O
20	O
pixels	O
,	O
any	O
rotation	O
or	O
skew	O
must	O
be	O
corrected	O
or	O
no	O
text	O
will	O
be	O
recognized	O
,	O
low-frequency	O
changes	O
in	O
brightness	O
must	O
be	O
high-pass	O
filtered	O
,	O
or	O
Tesseract	B-Language
's	O
binarization	B-Algorithm
stage	O
will	O
destroy	O
much	O
of	O
the	O
page	O
,	O
and	O
dark	O
borders	O
must	O
be	O
manually	O
removed	O
,	O
or	O
they	O
will	O
be	O
misinterpreted	O
as	O
characters	O
.	O
</s>
<s>
Tesseract	B-Language
is	O
executed	O
from	O
the	O
command-line	B-Application
interface	I-Application
.	O
</s>
<s>
While	O
Tesseract	B-Language
is	O
not	O
supplied	O
with	O
a	O
GUI	O
,	O
there	O
are	O
many	O
separate	O
projects	O
which	O
provide	O
a	O
GUI	O
for	O
it	O
.	O
</s>
<s>
One	O
common	O
example	O
is	O
OCRFeeder	B-Language
.	O
</s>
<s>
In	O
a	O
July	O
2007	O
article	O
on	O
Tesseract	B-Language
,	O
Anthony	O
Kay	O
of	O
Linux	B-Application
Journal	O
termed	O
it	O
"	O
a	O
quirky	O
command-line	B-Application
tool	I-Application
that	O
does	O
an	O
outstanding	O
job	O
"	O
.	O
</s>
<s>
At	O
that	O
time	O
he	O
noted	O
"	O
Tesseract	B-Language
is	O
a	O
bare-bones	O
OCR	O
engine	O
.	O
</s>
<s>
The	O
build	O
process	O
is	O
a	O
little	O
quirky	O
,	O
and	O
the	O
engine	O
needs	O
some	O
additional	O
features	O
(	O
such	O
as	O
layout	O
detection	O
)	O
,	O
but	O
the	O
core	O
feature	O
,	O
text	B-Application
recognition	I-Application
,	O
is	O
drastically	O
better	O
than	O
anything	O
else	O
I	O
've	O
tried	O
from	O
the	O
Open	O
Source	O
community	O
.	O
</s>
<s>
It	O
is	O
reasonably	O
easy	O
to	O
get	O
excellent	O
recognition	O
rates	O
using	O
nothing	O
more	O
than	O
a	O
scanner	O
and	O
some	O
image	O
tools	O
,	O
such	O
as	O
The	B-Application
GIMP	I-Application
and	O
Netpbm.	O
"	O
</s>
<s>
In	O
November	O
2020	O
,	O
Brewster	O
Kahle	O
from	O
the	O
Internet	O
Archive	O
praised	O
Tesseract	B-Language
saying	O
:	O
</s>
