Publications de Sylvain Chosson

Beating Shapes Relying on Moire Level Lines

We consider the problem of obtaining a recognizable shape as superposition moire of two line gratings. The method we propose generates moire lines located between the shape foreground and background centers and the shape boundaries. Upon relative displacem ...

Association for Computing Machinery2014

High-resolution 1D moirés as counterfeit security features

Jürgen Brugger, Roger Hersch, Katrin Sidler Arnet, Victor Javier Cadarso Busto, Sylvain Chosson

A moire is an interference pattern that appears when two different periodic structures are overlaid. The image created is extremely sensitive to small variations in the original layers and is thus very interesting for anti-counterfeit protection. We presen ...

Nature Publishing Group2013

Authentication of documents and articles by moire patterns

Roger Hersch, Sylvain Chosson

The present invention relies on the moiré patterns generated when superposing a base layer made of base band patterns and a revealing line grating (revealing layer). The produced moiré patterns comprise an enlargement and a transformation of the individual ...

2010

Printing color images visible under uv light on security documents and valuable articles

Roger Hersch, Sylvain Chosson, Philipp Donzé

In the present invention, we propose a method of creating fluorescent color images visible under UV light. It relies on the new colorants that can be achieved by superposing ink dots, possibly at a reduced size, in order to avoid quenching effects. It also ...

2008

Color images visible under UV light

Roger Hersch, Sylvain Chosson, Philipp Donzé

The present contribution aims at creating color images printed with fluorescent inks that are only visible under UV light. The considered fluorescent inks absorb light in the UV wavelength range and reemit part of it in the visible wavelength range. In con ...

2007

Synthesis of superposition images for watches, valuable articles and publicity

Roger Hersch, Sylvain Chosson

The present invention aims at synthesizing superposition images formed either by band moire shapes or by shape level lines for making the information forwarded by valuable articles or by time pieces such as watches and clocks more dynamic, as well as for i ...

2007

Authentication of secure items by shape level lines

Roger Hersch, Sylvain Chosson

The disclosed method and system may be used for creating advanced protection means for various categories of documents (e.g. bank notes, identity documents, certificates, checks, diploma, travel documents, tickets) and valuable products (e.g. optical disks ...

2006

Model-based synthesis of band moire images for authenticating security documents and valuable products

Roger Hersch, Sylvain Chosson

The present invention relies on a band moiré image layout model capable of predicting the band moiré image layer layout produced when superposing a base band grating layer of a given layout and revealing line grating layer of a given layout. Both the base ...

2006

Synthèse d'images moiré

Sylvain Chosson

We explore a new approach for synthesizing moiré images that can be used for authentication of documents. For synthesizing moiré images, we need two layers: a base layer made of replicated bands or parallelograms and a revealing layer made of transparent l ...

EPFL2006