
The patent on SIFT expired yesterday - groar
https://patents.google.com/patent/US6711293B1/en
======
skunkworker
Does this mean that OpenCV will be able to now include SIFT in the “free”
modules. Or are there more roadblocks before including it?

~~~
rsp1984
I'm not a lawyer, but as far as I know expired US patents enter the public
domain. After their expiration the described invention can be freely used by
anyone for any purpose [1].

So I think the answers to your questions are yes and no.

[1] [https://www.nolo.com/legal-encyclopedia/how-long-is-my-
paten...](https://www.nolo.com/legal-encyclopedia/how-long-is-my-patent-
protection-good-for.html)

~~~
amelius
Perhaps there are still patents in other regions (?)

~~~
dr_zoidberg
As others commented, the only countries where software patents work are the US
and Japan. So it'd be just Japan that could have a patent in place? Don't know
theh details, and IANAL.

OTOH, I'd really like the patent to be inactive, it'd allow me to work worry
free in a lot of things that I've had an interest in.

------
neonate
[https://en.wikipedia.org/wiki/Scale-
invariant_feature_transf...](https://en.wikipedia.org/wiki/Scale-
invariant_feature_transform)

------
MobileVet
Evolution Robotics (later acquired by iRobot) was the first licensee of this
patent for robotics applications. It was very cutting edge for the time and
allowed our robots the ability to recognize real world objects. Having the
robot follow a book that you carried in front of it was trippy in 2002.

Later we applied it to loss prevention in grocery retail with cameras at
ground level watching under the cart. If we recognized anything in the ‘bob’
(bottom of the basket) we would automatically add it to the receipt.

Good memories.

Edit: typo 'tea' -> real

~~~
black_puppydog
wait... the concept was to have video cameras on the ground point _upward_ in
a supermarket setting?

Did anyone involved in this ever stop to think "what would a person wearing a
skirt say to this?" It's not exactly the kind of thing you'd expect to be able
to explain away with "oh no but we really don't use it for that" no?

~~~
derivagral
A more charitable reading is that the cameras are at ground level and stay
aimed at ground level. I got the impression he's not talking about the main
basket of the shopping cart, but the storage right above the wheels where you
might forget pet food or bulk paper goods.

~~~
black_puppydog
okay, that might be my non-native English comprehension. I parsed "bottom of
the basket" as the flat underside of the main part of the cart. And you'd have
to point the cameras upwards to see that.

If it's horizontal, that's a different topic.

~~~
dr_zoidberg
I had the same impression upon first read. And from a programmers perspective
of what the ideal conditions for such a software would be, I also thought of a
ground placed camera, pointing upwards in a way in which id could see the
basket an find items that were "forgotten" in it.

------
echelon
How much money did the University of British Columbia actually earn from this
patent?

~~~
peter_retief
I suspect that many patents are to stop others from patenting your work. It is
a worry.

~~~
Reelin
Open publication (at least in western jurisdictions) serves as prior art. If
you don't intend to patent, just write about what you're doing openly and
often!

~~~
peter_retief
Can any publication serve as prior art? Can I use a personal blog or do I need
a certain type of publication? I know of people who have sent copies of their
work in the mail to themselves to prove prior art.

~~~
simonh
Any publication is fine as long as you can provide evidence. In fact the only
thing special about publication is that it is a convenient way to demonstrate
evidence of the prior art. What could be tricky about e.g. a personal blog
post is proving that it was published when you say it was and that time stamps
are genuine.

~~~
eitland
For those who are interested and doesn't know already[0] this is one of the
places where blockchains and similar, older technoologies are actually useful:
to provide irrefutable proof of knowledge at a given time.

Note however that similar services has been done for years[1] before Bitcoins
and blockchains became a thing but since they neither need multi-Gigawatt-
Proof-of-Work [2] nor any kind of "Coin" that can be pumped (and dumped) it
wasn't cool.

[0]: [https://xkcd.com/1053/](https://xkcd.com/1053/) (and hi to todays lucky
1/10000! : )

[1]: See here for an article that describes it:
[https://www.vice.com/en_nz/article/j5nzx4/what-was-the-
first...](https://www.vice.com/en_nz/article/j5nzx4/what-was-the-first-
blockchain)

[2]: but, it kind of works anyway since it would take quite some work to find
the majority + the archived ones of a certain days New York Times papers and
change the classifieds section.

~~~
IAmEveryone
I'm somewhat sure that prior art requires _publication_ , and not just
_knowledge_.

The internet archive has long been used as evidence for such publication-at-
time claims, and they even have a paid service allowing you to trigger
snapshots IIRC. There's a FAQ regarding the use of their data in court cases
that is somewhat interesting to read.

I know the cryptocurrency community has this absurd notion that nothing
without cryptographic proof could or should ever be regarded as evidence. That
trusting institutions, people, or processes marks you as a gullible fool, and
that the Federal Reserve is conspiracy by private banks to keep the gentile
from the levers of power[0].

So this is the not entirely novel situation of crypto being proposed to solve
a problem that doesn't exist, and failing due to the lack of (usually: active
hostility to) subject matter expertise.

[0] last point unrelated to this specific situation and just included for
completeness

~~~
eitland
> I know the cryptocurrency community has this absurd notion that nothing
> without cryptographic proof could or should ever be regarded as evidence.
> That trusting institutions, people, or processes marks you as a gullible
> fool, and that the Federal Reserve is conspiracy by private banks to keep
> the gentile from the levers of power[0]. So this is the not entirely novel
> situation of crypto being proposed to solve a problem that doesn't exist,
> and failing due to the lack of (usually: active hostility to) subject matter
> expertise.

It reads like you count me in with the cryptocurrency community.

If anyone else does: don't.

I'm pointing out one single place were blockchain can be useful and then
immediately pointing out that it isn't strictly necessary.

------
yantrams
Reddit discussion on this -
[https://www.reddit.com/r/computervision/comments/fednny/sift...](https://www.reddit.com/r/computervision/comments/fednny/sift_patent_expires_today/)

------
exikyut
More info about what this actually is: [https://en.wikipedia.org/wiki/Scale-
invariant_feature_transf...](https://en.wikipedia.org/wiki/Scale-
invariant_feature_transform)

\---

Also, reading the listing, I see

2020-03-06 - Anticipated expiration

2020-03-08 - Application status is Active

Is "active" some kind of obscure reference with a nonintuitive meaning, or did
the patent owner reapply for the patent?

~~~
mkl
You can't reapply for patents like that, but I don't know what that status
means. Patents often get an adjustment to their term and last a bit more than
their nominal 20 years (due to delays being issued, etc.).
[https://en.wikipedia.org/wiki/Term_of_patent](https://en.wikipedia.org/wiki/Term_of_patent)

------
mrfusion
Anyone know other major patents expiring in the next few years? ( or that have
expired recently?)

It could make an interesting hn thread.

------
alexcnwy
SIFT works really well.

We use it for aligning input documents onto templates for OCR.

Super cool.

~~~
speculatrix
how did you go about licencing the patent?

~~~
alexcnwy
Didn’t, was just RND.

------
nullc
One time on caltrain I was amused by some very drunk people trying to explain
how SIFT works to each other.

------
herf
You can still download the autostitch app - have used it several times for
one-off panos:

[http://matthewalunbrown.com/autostitch/autostitch.html](http://matthewalunbrown.com/autostitch/autostitch.html)

------
DaiPlusPlus
To what extent were the SIFT patents enforced?

As an undergraduate I worked as an RA for some (IEEE published) research at my
uni for some robotics work and I gather that violating the SIFT patent was
somewhat common when it wasn't obvious SIFT was being used, e.g. when SIFT was
being used as a fungible solution:

Self-driving car demo that recognizes road-signs? No, that's too obvious.

Object recognition primarily using HOG or other approaches but using SIFT as a
fallback or for determining a confidence value? Go ahead.

And SIFT was used in a lot of private projects (proof-of-concepts, etc) or lab
workers' weekend personal projects. This was in academia, but I'm curious if
this attitude extends to industry anywhere.

~~~
unishark
The way patents are enforced is the patent holder sues for damages. This
obviously means there needs to be some damages, i.e. they claim they lost
sales or something. If you aren't using the patent to make products or money,
just to do research, this is a hard case to make. I wonder if it actually ever
happens in academia.

Note that everything you "invent" that builds on the prior patent, including
what you publish, is still blocked by that patent. And even if you ultimately
remove the patented part, they can claim it was needed in the research
process. So wantonly infringing on a patent in your research doesn't hurt the
patent holder anyway.

~~~
gaogao
The research exemption used to be quite broad especially for universities who
would often use it as carte blanche, but was narrowed significantly by Madey
v. Duke University.

------
aerodog
There have been many better feature detectors introduced in the mix over the
past fifteen years. This change won't make too big a difference for people in
the CV community.

~~~
Rochetshipz
Mhhhhh, I'm a researcher in the field and I'd say it's a mostly inaccurate
statement. The root-SIFT detectors and descriptors are still really good. If
you try to match images in different conditions (day/night), then CNN based
approaches are OK.

Which one were you thinking about?

~~~
johntiger1
I would argue more that SIFT was valuable in introducing a new paradigm of
feature extraction/matching. It is a staple of many computer vision courses.
But yes the main algorithm I'm sure is quite (practically) performant as well

------
donohoe

      2020-03-09 
      Application status is Active
    

Not anymore

~~~
rkangel
I don't understand what this means. US Patents are 20 years, right? And it was
applied for in 1999, so it must be expiring?

~~~
donohoe
Perhaps. I'm just pointing out (badly) that when this was posted (March 8th
depending on Timezone) to HN that new status may not have been there. That
latest status updated just happened March 9th.

------
chewxy
TIL SIFT was patented. I wonder if SURF was as well. Not that it matters
nowadays

~~~
throwlaplace
yes it is

>In computer vision, speeded up robust features (SURF) is a patented local
feature detector and descriptor.

[https://en.m.wikipedia.org/wiki/Speeded_up_robust_features](https://en.m.wikipedia.org/wiki/Speeded_up_robust_features)

------
brokensegue
Is sift still relevant today?

~~~
alleycat5000
There's a good paper on this:

[https://demuc.de/papers/schoenberger2017comparative.pdf](https://demuc.de/papers/schoenberger2017comparative.pdf)

"Our evaluation confirms that, as expected, learned descriptors often surpass
SIFT on all evaluation metrics. However, we also observe that advanced
versions of hand-crafted descriptors perform on par or better than the state-
of-the-art learned feature descriptors, especially in the more complex SFM
scenarios. As such, our paper demonstrates that there is still significant
room for improvement for learning more powerful feature descriptors."

~~~
Rochetshipz
This paper is a bit "old" by the way. An excellent paper was released a week
ago : [https://arxiv.org/abs/2003.01587](https://arxiv.org/abs/2003.01587)

Findings are mostly the same. For day/day images, with a properly tuned
pipeline, SIFT is really good.

