static void
_f_do_barnacle_install_properties(GObjectClass
*gobject_class)
{
OCRFeeder
GParamSpec *pspec;
/* Party code attribute */
pspec = g_param_spec_uint64
(F_DO_BARNACLE_CODE,
"Barnacle code.",
"Barnacle code",
0,
G_MAXUINT64,
G_MAXUINT64 /*
default value */,
Documents conversion on GNOME
G_PARAM_READABLE
| G_PARAM_WRITABLE |
G_PARAM_PRIVATE);
g_object_class_install_property (gobject_class,
F_DO_BARNACLE_PROP_CODE,
Joaquim Rocha
jrocha@igalia.com
FOSDEM 2010

What is it?
Document Analysis and Optical
Character Recognition
for GNOME
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Why is it?
Paper has a number of problems
No applications for GNU/Linux to do
a fair job
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Paper problems:
Security
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010
CC Photo by: http://www.flickr.com/photos/badwsky/

Paper problems:
Preservation
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010
CC Photo by: http://www.flickr.com/photos/98469445@N00/

Paper problems:
Data processing
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010
CC Photo by: http://www.flickr.com/photos/hugovk/

Paper problems:
Ecology
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010
CC Photo by: http://www.flickr.com/photos/pranavsingh/

No fair conversion apps for
GNU/Linux
apart from OCR engines, but...
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

OCR != Document Conversion
(it only deals with chars)
(does not consider the layout)
(does not distinguish contents)
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

what you want is
Document Analysis and
Recognition
(conversion of documents to an
electronic format)
(first projects in the 80s)
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Where are were we at?
* Some closed solutions
* Only for proprietary systems
* Various prices
* still... arguable results
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

How?
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

How
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Base concept:
1. Clip the contents
2. Classify them
2.1. They are graphics → Paste on
document
2.2. They are text → Calculate letter
size; paste on document
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

So many layouts...
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010
CC Photo by: http://www.flickr.com/photos/uber-tuber/

Layouts vary with the type of
document
What works on detecting one, won't
work on others
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

OCRFeeder focus on contents, not
on layouts!
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Key concept:
If a document image can be
divided in windows of 1 (content)
or 0 (not content),
then it is possible to group all the
1s and outline the contents
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Sliding Window Algorithm:
1. A NxN pixel window runs through
the document top to bottom, left to
right
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Sliding Window Algorithm:
2. For every iteration, if there's a
pixel inside the window which
contrasts with the background,
then the window gets a 1,
otherwise it gets a 0
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Sliding Window Algorithm:
It does not check all the pixels so
there is a better performance
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Sliding Window Algorithm:
3. After all windows
have a value assigned,
the ones with the value 1 are
grouped
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Sliding Window Algorithm:
4. Every time a set of 1s is
grouped, each window is
reassigned the value 0
(these are called blocks)
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Sliding Window Algorithm:
5. When all windows have
the value 0, the algorithm
reached the end
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Block structure:
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Joining Blocks:
Blocks are check with each other
and joined when appropriate
When no blocks can be joined the
analysis part is finished
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Recognition:
System-wide OCR engines are used
Engines are configured from the
GUI or XML files
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Engine configuration:
<?xml version="1.0" encoding="UTF-8"?>
<engine>
<name>Tesseract</name>
<image_format>TIFF</image_format>
<engine_path>/usr/bin/tesseract</engine_path>
<arguments>$IMAGE $FILE; cat $FILE.txt;
rm $FILE.txt</arguments>
</engine>
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Classification:
It is graphics if:
* Text is empty
* More than 50% of the chars are
failure chars, punctuation or spaces
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Font Size Detection:
“Measures” in pixels the size of
each text line
Although it results in different
sizes...
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Font Size Detection:
The value equal or greater than the
average is chosen
(results in values equal or close to
the original font size)
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Font Size Detection:
The font size is calculated in inches
using the resolution (DPI)
(if there's no resultion info, assume
300 DPI)
The value is then divided by the
DTP (DeskTop Publishing point): 72
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Exportation to ODT:
Uses ODFPy
(abstracts ODF creation)
(just above XML)
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

User interaction:
Users can edit everything
and review the algorithm's results
So, UI can work in attended and
unattended ways
CLI only works in an unattended
mode
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

ABBY Finereader test
Nuance Omnipage test
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Finereader's
results
Omnipage's
results
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Demo time!
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Other features:
* PDF importation
* Unpaper preprocessor
* Font style edition
* Exportation to HTML
* Project saving/loading
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Future:
* Integrate Ocropus as an
alternative analysis backend
* More exportation formats: HOCR,
txt, PDF
* Improved a11y
* Better integration with GNOME
and other GNOME apps
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

GNOME:
Development moved to GNOME's
infrastructure since last month
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Webpage:
http://live.gnome.org/OCRFeeder
git:
http://git.gnome.org/ocrfeeder
Bugzilla:
coming soon...
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010

Thank you!
Joaquim Rocha (Igalia) · OCRFeeder · FOSDEM 2010