Publications by Roger Hersch | EPFL Graph Search

Demichel Equations

Springer International Publishing2023

Synthesis of moving and beating moiré shapes

Roger Hersch, Jürgen Brugger, Thomas Walger

The present invention proposes a method for producing an authenticable moiré shape that simultaneously moves and shows a beating effect. The method relies on a combination of the 1D or the 2D moiré and the level line moiré. When tilting a compound showing ...

2022

2d-3d sculpture paintings

Roger Hersch, Sabine Süsstrunk, Mahmut Sami Arpa

We disclose a method for synthesizing by computer an artwork where 2D and 3D contents are integrated within a same composition. Such an artwork creates plausible effects for the viewers by showing a different relationship between 2D and 3D at each viewing ...

2020

Level-line moirés by superposition of cylindrical microlens gratings

Roger Hersch, Jürgen Brugger, Valentin Flauraud, Théophane Besson, Thomas Walger

Two superposed layers of transparent cylindrical lenslet gratings create classical moiré fringes when illuminated from behind. We rely on this observation to conceive special devices made of superposed lenslet gratings that produce compelling beating shape ...

2020

Fabrication of moire on curved surfaces

Roger Hersch, Vahid Babaei

Moire is an appealing visual effect observable when two or more repetitive patterns are superposed. Fabrication of moire effects has already proven to be useful in a range of applications, from art to engineering. Here, we introduce a method for designing ...

2020

Angular Color Prediction Model for Anisotropic Halftone Prints on a Metallic Substrate

Roger Hersch, Petar Pjanic, Lin Yang

Under specular reflection, non-isotropic halftones such as line halftones printed on an ink-receiving plastic layer superposed with a metallic layer change their colors upon in-plane rotation of the print. This color change is due to the orientation-depend ...

I S & T-SOC IMAGING SCIENCE TECHNOLOGY2019

Synthetic electronic video containing a hidden image

Roger Hersch, Sabine Süsstrunk, Mahmut Sami Arpa

We present a method for hiding images in synthetic videos and reveal them by temporal averaging. We developed a visual masking method that hides the input image both spatially and temporally. Our masking approach consists of temporal and spatial pixel by p ...

2019

1D moiré shapes by superposed layers of micro-lenses

Roger Hersch, Jürgen Brugger, Valentin Flauraud, Théophane Besson, Thomas Walger

Two superposed layers of transparent cylindrical lenslet gratings create classical moiré fringes, when illuminated from behind. We rely on this observation to conceive special devices made of superposed lenslet gratings that produce animated moirés when th ...

2019

Sculpture paintings

Roger Hersch, Sabine Süsstrunk, Mahmut Sami Arpa

ACM2018

Color changing effects with cross-halftone prints

Roger Hersch, Petar Pjanic

We propose new methods for creating color varying prints with classical cyan, magenta, yellow inks on a metallic specularly reflecting or on a white diffusely reflecting substrate. We use a special cross-line halftone with optimized surface coverages of th ...

2017

Revealing Information by Averaging

Roger Hersch, Sabine Süsstrunk, Mahmut Sami Arpa

We present a method for hiding images in synthetic videos and reveal them by temporal averaging. The main challenge is to develop a visual masking method that hides the input image both spatially and temporally. Our masking approach consists of temporal an ...

Optical Soc Amer2017

Synthesis of superposition shape images by light interacting with layers of lenslets

Roger Hersch, Jürgen Brugger, Valentin Flauraud, Théophane Besson, Thomas Walger

The present invention describes methods and apparatuses for creating superposition shape images by superposed base and revealing layers of lenslet gratings. The superposition shape images form a message recognizable by a human observer or by an image acqui ...

2017

Color changing effects with cross-halftone prints on metal

Roger Hersch, Petar Pjanic

We propose new methods for creating color varying prints with classical cyan, magenta, yellow inks on a metallic substrate. We use a special crossline halftone with optimized surface coverages of the inks to create color prints on a metallic surface whose ...

2017

Color reproduction, pattern hiding and image alternations with halftone prints on metal

Roger Hersch, Petar Pjanic

We propose new methods for creating color or achromatic images that are printed with classical cyan, magenta, yellow and a white diffusing ink on a metallic substrate. We optimize the surface coverages of the cyan, magenta, yellow and white inks in order t ...

2016

Multilayer four-flux matrix model accounting for directional-diffuse light transfers

Roger Hersch, Mathieu Hébert

The four-flux model is a method to solve light radiative-transfer problems in planar, possibly multilayer structures. The light fluxes are modeled as two collimated and two diffuse beams propagating forward and backward perpendicularly to the layer stack. ...

Optical Soc Amer2016

High Relief from 3D Scenes

Roger Hersch, Sabine Süsstrunk, Mahmut Sami Arpa

We present a method for synthesizing high reliefs, a sculpting technique that attaches 3D objects onto a 2D surface within a limited depth range. The main challenges are the preservation of distinct scene parts by preserving depth discontinuities, the fine ...

Wiley-Blackwell2015

Color Reproduction of Authenticable Luminescent Backlit Transmissive Color Images

Roger Hersch, Julien Alexandre Andres

We propose a method for creating authenticable color images under UV excitation backlight by printing an invisible luminescent white emissive ink layer on the verso side of a transmissive substrate and a classical cmy image on the recto side of the substra ...

Wiley-Blackwell2014

Synthesis of authenticable halftone images with non-luminescent halftones illuminated by an adjustable luminescent emissive layer

Roger Hersch, Julien Alexandre Andres

A method and computing system are proposed for producing an authenticable security device with two sides. The verso side is covered with an adjustable luminescent emissive layer formed by invisible luminescent ink halftones and possibly a UV absorbing prin ...

2014

Jaggies as aliasing or reconstruction phenomena: a tutorial

Isaac Amidror, Roger Hersch

Jaggies (staircasing effects) along slanted lines or curved edges are omnipresent in digital imaging. They are so widespread in digital display devices that very often they are associated with the modern "computerized" world (and sometimes even intentional ...

Is&T & Spie2014

Recovering Neugebauer colorant reflectances and Ink-spreading curves from printed color images

Roger Hersch, Thomas Bugnon

Spectral reflection prediction models, although effective, are impractical for certain industrial applications such as self-calibrating devices and online monitoring because their calibration requires specific color-constant calibration patches. Using the ...

Wiley-Blackwell2014