Invisible digital watermark

[Pat David]

Fourier watermarking is highly susceptible to being destroyed during resize
operations, as the image scale and frequencies all shift pretty heavily.

Wavelets aren't patented per se, I think, but I still don't know that they
are going to solve OP's question.

If you want a truly invisible watermark, don't share the image.  If you
_must_ have something to "protect" you, then don't share the full
resolution or raw file (you can always produce a higher resolution image or
raw file to "prove" ownership.

Alternatively, creatively add your watermark directly into the image
somewhere that won't be easy to notice, but might survive further editing.

Better still - maybe don't use a watermark at all? :)

On Fri, May 12, 2017 at 11:29 AM Gilles Caulier <caulier.gilles at gmail.com>
wrote:

> Simon,
>
> Photoshop have a tool to watermark photo before to publish this on the
> web. It's in relation with a web service to identify a copyright photo
> everywhere though the web.
>
> Of course the service is not free...
>
> https://www.digimarc.com/application/photography
>
> Gilles
>
> 2017-05-12 18:16 GMT+02:00 Simon Frei <freisim93 at gmail.com>:
> > I don't know anything about how it works, I just had a hunch that this
> > would be something that could be in G'MIC - and it was. You best ask the
> > G'MIC folks about it.
> >
> > Honestly, I don't really consider this very useful in the real world.
> > The party where you proclaim a copyright breach has to use G'MIC digiKam
> > to recover the copyright information, which they probably won't, and a
> > simple proof of ownership by comparing to an "original" (higher res,
> > raw, ...) picture is probably sufficient. If your picture is that
> > valuable, the "thief" will probably also go trough the trouble of
> > removing your notice from the fourier domain (which probably is
> > possible, as it is fourier and the original transformation
> > implementation is known).
> >
> > On 12/05/17 15:17, Sveinn í Felli wrote:
> >> Maybe something similar to image steganography could be used?
> >> That is a process where one can embed encrypted message/image into a
> >> picture. Pixelknot is such an OSS-application for Android, see
> >> <https://guardianproject.info/apps/pixelknot/>
> >>
> >> Simon, do you know how well the Fourier markings survive through
> >> modifications by image sharing services?
> >>
> >> Regards,
> >> Sveinn í Felli
> >>
> >> Þann fös 12.maí 2017 12:38, skrifaði Louis A. Turk:
> >>> On 05/12/2017 07:05 PM, Gilles Caulier wrote:
> >>>> Very interesting. Please comment this entry in bugzilla accordingly :
> >>>>
> >>>> https://bugs.kde.org/show_bug.cgi?id=268981
> >>>>
> >>>> Thanks in advance
> >>>>
> >>>> Gilles Caulier
> >>>>
> >>>> 2017-05-12 12:03 GMT+02:00 Simon Frei <freisim93 at gmail.com>:
> >>>>> There is a G'MIC filter that embeds text in the fourier domain, it is
> >>>>> called "Fourier watermark" (and "Fourier analysis" to retrieve the
> >>>>> info): https://gmicol.greyc.fr/
> >>>>>
> >>>>> On 12/05/17 11:35, Gilles Caulier wrote:
> >>>>>> You cannot. Invisble watermark use wavelets encoding methods which
> >>>>>> are
> >>>>>> patented in US and impossible as i know to code in open source...
> >>>>>>
> >>>>>> Best
> >>>>>>
> >>>>>> Gilles Caulier
> >>>>>>
> >>>>>> 2017-05-12 10:42 GMT+02:00 Louis A. Turk
> >>>>>> <louisaturk at firmanelohim.org>:
> >>>>>>> How can I do invisible digital watermarking with digikam5 as
> >>>>>>> mentioned
> >>>>>>> here:
> >>>>>>>
> https://docs.kde.org/trunk5/en/extragear-graphics/digikam/using-dam.html#using-dam-copyright
> >>>>>>>
> >>>>>>>
> >>>>>>> How can I do a regular watermark?
> >>>>>>>
> >>>>>>> drl
> >>>>>
> >>>>>
> >>>
> >>> Thank you Gilles and Simon. Hopefully, the impossible may be possible
> >>> after all.
> >>>
> >>> drl
> >>>
> >>
> >
> >
>
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