Frequently Asked Questions

If you have a question not answered in here, please ask by email.


How should IPOL as a journal be identified and cited?

IPOL as a whole can be identified by its ISSN: 2105-1232, or its DOI: 10.5201/ipol. The latter should be used for all academic references to IPOL.

Image Processing On Line. ISSN:2105-1232,

    title = {{Image Processing On Line}},
    key = {IPOL},
    url = {},
    issn = {2105-1232},
    doi = {10.5201/ipol},
% if your bibliography style doesn't support url, issn and doi
% fields, use "howpublished" and "note" alternatives,
% here with the hyperref package
    howpublished = {\url{}},
    note = {ISSN:2105-1232, \url{}},

How should an IPOL article be identified and cited?

IPOL published articles are identified by their DOI. For a (fictional) article with DOI 10.5201/ipol.abcde:

J. Doe. A New Denoising Algorithm. Image Processing On Line, 2010.

    title = {{A New Denoising Algorithm}},
    author = {Doe, J.},
    journal = {{Image Processing On Line}},
    year = {2010},
    doi = {10.5201/ipol.abcde},
% if your bibliography style doesn't support doi fields, use the
% "note" alternative, here with the hyperref package 
    note = {\url{}},

How should an IPOL preprint be identified and cited?

IPOL preprints can be identified by their title, for example:

J. Doe. A New Denoising Algorithm. Image Processing On Line, 2010, preprint.

    title = {{A New Denoising Algorithm}},
    author = {Doe, J.},
    year = {2010},
    note = {preprint},


Why are there two versions of the PDF manuscripts?

The default version is adapted to a visualization on a computer screen. The images have been downsampled to 96 dpi. This results in smaller PDF files, fast download, and fast rendering.

But if you want to print the document, or examine the details of embedded images, or extract these images from the PDF file, you should use the high-resolution version. The images are embedded in this PDF file exactly as they were provided by the authors, sometimes with a very high resolution. The size of this PDF file can be substantially larger than the default version, and require more time to download and render.

How are the video files encoded? How can I read them?

Video files distributed as supplementary materials are H.264/MPEG-4 AVC files: H.264 video codec in a MPEG-4 container. They can be read with most of the modern video players.

One notable exception is QuickTime, which doesn't support some advanced H.264 features. We try to produce QuickTime-compatible video files, but if you experience issues, please try with another player, such as VLC.

I have a problem with the source code provided with an article. Can you help me?

For any matter regarding the content of an article, including the software published in this article, you should refer to the authors. Their name, affiliation, and email address are provided for every article.


Why are there some missing images or some empty archives?

Someone started using a demo but did not continue until the last steps. Or a demo failed. Or someone tried to upload a heavy image, which was rejected.

The archiving system is very primitive. An improvement is planned as part of future developments.

Can I delete some archives?

No you can't. But the IPOL administrators can. If you want to delete some data, for any reason, just send then the archive identifiers (the random string ae6888cb1904...) by email.

Who is responsible for the content of the public archives?

The public archives are automatically published, IPOL hosts these images without any a priori moderation or editorial control. As explained on archive pages, we remove any content upon request. So far, after 2 years, very few questionable content (<0.1%) had to be removed from the archives.


Can I publish on line an original code written by other authors?

You can publish on line a code written by other authors if its licence authorizes free use and corrections (for instance a GPL license). Thus doing, you must respect the authors' rights and quote them and their work adequately. If the published code is close enough to the original, we encourage you to gracefully ask the original authors to become co-authors of the IPOL publication.

Can I submit simple and standard algorithms?

Simple and standard algorithms will be accepted in IPOL as much as they are judged technically and scientifically useful, and as the implementation and on line demo are well conceived and well documented.

Can I submit an algorithm which I have also published, or intend to publish, in a classic computer vision journal?

Yes you can. The on line publication of your algorithm has other constraints and requirements different from a journal publication. It is considered complementary.


Can I publish my source code under a free license and sell it under a commercial license?

Yes! A free software license is not exclusive. The authors can distribute their work under the GPL license and sell the right to use this software under a commercial agreement to a partner who prefers not to be bound by the GPL terms.

What is copyrighted? The source code or the algorithm?

Algorithms can not be copyrighted. The copyright applies to the creative work expressed in the source code, not to the algorithm implemented by the source code. You can write your original implementation of any algorithm and own the copyright of this work.

What about patents?

There is no software patent in Europe, ie no software is patentable, no software can constitute a patent infringement. And most countries exclude research and experimentation from patent restrictions.

See the IPOL Software Guidelines for more details.


Why can a MATLAB code not be published in IPOL?

Because there are as many versions of the MATLAB language as there are many releases of the Matlab software (2/year); without a stable and complete definition of the language, no code written in MATLAB can be assured to work in the future. Authors can anyway make available a MATLAB code in addition to their submitted C or C++ code, and in that case it will also be made public by IPOL.

Moreover, supporting MATLAB would require to adapt the IPOL Software Guidelines and expand the current demo system to support such implementations, and IPOL cureently doesn'have the workforce for these tasks.

How must the algorithm code handle image input/output for the web demo?

The algorithm code doesn't need be adapted to a web demo environment. This code just need to read and write one image format. As long as it is a standard format (TIFF, PNG, PGM, ...), converting from and to this format will be handled by the demo environment.

See the IPOL Software Guidelines for more details.

I don't know how to read and write image files. Can IPOL provide an example?

Some code is available in the IPOL wiki, to read/write PNG and TIFF images.

Can I use the libfoo library?

If you include it with the code, yes, but it will be very hard to read and review. You had better only include the parts of this library you actually use. See the IPOL Software Guidelines for more details.

Publishing in IPOL requires more work than publishing in other journals. Your conditions on the source code are too strict.

Yes, IPOL requires more work from the authors, but you publish more material in IPOL than in other journal, and we believe it's worth doing it, and other journals should adopt similar policies. The conditions are strict, but they are the price to pay for long-term usability.

Current authors seem satisfied by their IPOL experience. The extra work required on the implementation is acceptable and it brings appreciated benefits. See the 2011 Author Feedback for more details.

I only work with Windows (resp. Linux), I don't think Linux (resp. Windows) compatibility is important.

Some researchers do really work with Windows, ans some other with Linux. And Mac OSX too. We can't ignore any of these environments, it would be like writing an article in a language understood by only 30% of the research community.

See the 2011 Author Survey for more details.

I don't want to show my source code but I want to show it works in an IPOL article and demo.

If we can't read your code, we can't know how it really works, it is not a content IPOL wants to publish.