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restoring 2012 April fool's joke
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MoniqueTeillaud committed May 15, 2024
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---
layout: post
title: "Biometry application"
description: "What we do is not evil."
category: "news"
tags: []
---
{% include JB/setup %}

<p>
April 1st, 2012
<p>

<p>
Dear CGAL developers, Dear CGAL users,
</p>

<p>
In order to put an end to rumors about GeometryFactory
selling CGAL to Facebook for a biometry application,
let me give you the background, and let me explain why
we think that what we do is not evil.
</p>

<p>
Just as nuclear energy can be good or bad, biometry is
neutral as such. The particular application we contribute
to is about matching lip prints on cigarette butts with
Facebook users who threw the butts away. This allows people
to act, who are fed up with cigarette butts lying around
virtually everywhere: in front of the Statue of Liberty,
as well as along trails in Yellowstone National Park.
</p>

<p>
One of the goals of social networks is social engineering,
that is making mankind better. The workflow of the
biometry application is
<br> 1 that you take a picture of a cigarette butt lying at a
place where it should not,
<br> 2 that you upload this picture to FB together with the GPS
coordinate of where you shot the picture, so that FB can
identify the culprit by matching the lip print on the
cigarette butt with the extensive database of faces.
<br>3 that FB tells him or her that this is not a well educated
behavior (smokers in fact know that it is not nice), and
puts repeat offenders on a wall of shame.
</p>

<p>
As it is technically rather fascinating, let me just
tell you why it is not a trivial problem. We can't reveal
all the details as we filed a patent. Lips leave prints,
just like fingers do, but fingers tips are flat compared
to lips, cigarettes are cylindrical, the max curvatures
of lips and cigarettes are mostly orthogonal where
they touch. Just as maps are distorted towards the poles,
so are the photos of lips and cigarette butts. Additionally,
only a small part of the lips touches the cigarette,
only one side of a cigarette butt is visible, and it needs
several uploaded photos of FB users to get a high
fidelity lip model. To get a grip on the orthogonal
curvatures and distortion we throw in the anisotropic
surface mesh generator Jane Tournois works on, and
we implemented the Lipschitz distance estimator to
get the confidence value for the lip-cigarette-butt match.
</p>

<p>
FB opted for CGAL, as the exact computing paradigm
helps to avoid false negatives (FB has to avoid accusing
people who not even smoke). The floating point filters
are key to not only being exact but also fast, as there
are millions of smokers who have to be identified.
Obviously, FB combines that with yellow-finger detection,
the timeline information they have ("Hey, I am in Venice"),
and whatever other data available.
</p>

<p>
As I wrote in the beginning, biometry is not evil as
such, and improving society seems a more moral goal
to us than target advertising. Similar applications
we have in mind, are the detection of counterfeit Dolce
and Gabana glasses, Lacoste T-shirts, and Louis Vuitton
handbags. FB Singapore pointed out that identifying
chewing gums on the sidewalk would interest them, but
it is not clear yet how to adapt the Lipschitz distance
estimator.
</p>

<p>
It was a mistake not to have discussed this at the last
CGAL developer meeting or openly in the forums, but I
had not expected such strong reactions when some of you
heard from Jane that we work on "some biometry stuff".
</p>

<p>
best regards,
</p>

<p>
andreas
<br>--
<br>Andreas Fabri, PhD
<br>Chief Officer, GeometryFactory
<br>Editor, The CGAL Project
</p>

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