The Clara OCR FAQ
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WELCOME

These are the Clara OCR Frequently Asked Questions. They're
useful for a first contact with Clara OCR. If you're looking for
information on how to use Clara OCR, please try the Clara OCR
Tutorial instead. Clara OCR can be found at http://www.claraocr.org/.

CONTENTS

1. What is Clara OCR?
2. Why is Clara a "cooperative OCR"?
3. Is Clara OCR Free? Open Source?
4. Is Clara OCR a GNU program?
5. On which platforms does Clara OCR run?
6. Does Clara OCR run on KDE? GNOME?
7. Does Clara OCR has a command-line interface?
8. Which languages are supported by Clara OCR?
9. Does Clara OCR support Unicode?
10. Is Clara OCR omnifont?
11. How does Clara differ from other OCRs?
12. How can I scan paper documents using Clara OCR?
13. I've tried Clara OCR, but the results disappointed me
14. How can I get support on Clara OCR?
15. Does Clara OCR induce to Copyright Law infringements?
16. How can I help the Clara OCR development effort?

1. What is Clara OCR?

Clara is an OCR program. OCR stands for "Optical Character
Recognition". An OCR program tries to recognize the characters
from the digital image of a paper document. The name Clara stands
for "Cooperative Lightweight chAracter Recognizer".


2. Why is Clara a "cooperative OCR"?

Clara is a cooperative OCR because it offers an web interface for
training and revision, so these tasks can benefit from the
revision effort of many people across the Internet. However,
Clara OCR also offers a powerful X-based GUI for standalone
usage.


3. Is Clara OCR Free? Open Source?

Clara OCR is distributed within the terms of the Gnu Public
License (GPL) version 2. Yes, Clara OCR is Free. Yes, Clara OCR
is Open Source. Clara OCR is not "Shareware", nor "Public
Domain".


4. Is Clara OCR a GNU program?

Clara OCR is unrelated to the GNU Project but its development is
strongly based on GNU programs (GCC, Emacs and others), as well
as on other free softwares, like the Linux kernel and XFree86.

Clara OCR is free software because we agree on the free software
ideal as stated by the GPL. To make this agreement explicit we
also adopted some suggestions from the Free Software
Foundation. These suggestions apply to the Clara OCR
documentation:

(a) GPL programs are referred as "free software", not "open
source".

(b) The term "GNU/Linux (operating system)" is used rather
than "Linux (operating system)".

(c) We do not recommend non-free softwares and do not refer
the user to non-free documentation for free softwares.

Furthermore, Clara OCR will support Guile as an extension
language in the near future.

Obs. We write "free software" instead of "open source"
just for coherence. We dislike antagonisms between the various
initiatives created along the years to freely produce, use,
change and distribute software.


5. On which platforms does Clara OCR run?

Clara OCR is being developed on 32-bit Intel running GNU/Linux.
Currently Clara OCR won't run on big-endian CPUs (e.g. Sparc) nor
on systems lacking X windows support (e.g. MS-Windows). A
relatively fast CPU (300MHz or more) is recommended.


6. Does Clara OCR run on KDE? GNOME?

Clara OCR will hopefully run on any graphic environment based on
Xwindows. That includes KDE, GNOME, CDE, WindowMaker and
others. Clara OCR depends only on the X library, and does not
require GTK, Qt or Motif to run. Clara OCR has been successfully
tested on X11R5 and X11R6 with twm, fvwm and others.

7. Does Clara OCR has a command-line interface?

Yes, but the X Windows headers and libraries are required anyway
to compile the source code, and the X Windows libraries are
required to run Clara OCR, even through the command-line
interface. So it's not possible to detach the GUI in order to
compile Clara OCR on systems that do not support X Windows.


8. Which languages are supported by Clara OCR?

As a generic recogniser, Clara OCR may be tried with any language
and any alphabet. However, there are some restrictions. Currently
Clara OCR expects the texts to be written horizontally, and there
are some heuristics that suppose some geometric relationships
typical for the Latin Alphabet and their accents, as used by
various european languages. Support for language-specific spell
checking is expected to be added soon.


9. Does Clara OCR support Unicode?

No, Clara OCR does not support Unicode, and the support to the
ISO-8859 charsets is partial.


10. Is Clara OCR omnifont?

No, Clara OCR is not omnifont. Clara OCR implements an OCR model
based on training. This model makes training and revision one
same thing, making possible to reuse training and revision
information (see also the next question).


11. How does Clara differ from other OCRs?

This is a quote from the Clara Advanced User's Manual:

Clara differs from other OCR softwares in various aspects:

1. Most known OCRs are non-free and Clara is free. Clara focus
the X windows system. Clara offers batch processing, a web
interface and supports cooperative revision effort.

2. Most OCR softwares focus omnifont technology disregarding
training. Clara does not implement omnifont techniques and
concentrate on building specialized fonts (some day in the
future, however, maybe we'll try classification techniques that
do not require training).

3. Most OCR softwares make the revision of the recognized text a
process totally separated from the recognition. Clara
pragmatically joins the two processes, and makes training and
revision parts of one same thing. In fact, the OCR model
implemented by Clara is an interactive effort where the usage of
the heuristics alternates with revision and fine-tuning of the
OCR, guided by the user experience and feeling.

4. Clara allows to enter the transliteration of each pattern
using an interface that displays a graphic cursor directly over
the image of the scanned page, and builds and maintains a mapping
between graphic symbols and their transliterations on the OCR
output. This is a potentially useful mechanism for documentation
systems, and a valuable tool for typists and reviewers. In fact,
Clara OCR may be seen as a productivity tool for typists.

5. Most OCR softwares are integrated to scanning tools offerring
to the user an unified interface to execute all steps from
scanning to recognition. Clara does not offer one such integrated
interface, so you need a separate software (e.g. SANE) to
perform scanning.

6. Most OCR softwares expect the input to be a graphic file
encoded in tiff or other formats. Clara supports only raw PBM.


12. How can I scan paper documents using Clara OCR?

You cannot. Clara OCR includes no support for scanners. To scan
paper documents, use another software, like the one bundled with
your scanner, or SANE (http://www.mostang.com/sane/). The
development tests are using SANE.


13. I've tried Clara OCR, but the results disappointed me

All OCR programs will disappoint you depending on the texts
you're trying to recognize. If you're a developer, join the Clara
OCR development effort and try to make it behave better on your
texts. If your are not a developer, wait a new version and try
again.


14. How can I get support on Clara OCR?

If the documentation did not solve your problems, try the
discussion list.


15. Does Clara OCR induce to Copyright Law infringements?

No. Clara OCR is just a tool for character recognition like many
others that can be purchased or are bundled with scanners. The
Clara OCR Project claims all users to be aware about the
Copyrigth Law and not infringe it. The Clara OCR Project
abominates any try to infringe the legitimate laws of any
country.

Nonetheless, the Clara OCR Project supports the free and public
availability of materials produced to be free, or of materials
out of copyright due to its age. The Clara OCR Project recognizes
the right of anyone to produce free or non-free materials.


16. How can I help the Clara OCR development effort?

The best way is to use Clara OCR to recognize the texts you're
interested on, and try to make it adapt better to them. The
Developer's Guide should help in this case (C programming skills
are required). The Clara OCR Project acknowledges all efforts to
make Clara OCR more widely known and used.


