Skip to Main content Skip to Navigation
Theses

Modèles spectraux à transferts de flux appliqués à la prédiction de couleurs sur des surfaces imprimées en demi-ton

Abstract : The protection of banknotes or identity documents against counterfeiting demands the development of control tools based on visual effects that are continuously renewed. These visual effects become thus difficult to counterfeit even by an expert forger ! This research tries to deal with that issue. Its objective is to bring new solutions using on the one side, the printing of diffusing materials, and on the other side the development of visual rendering models that can be observed. The visual effects that are sought-after are the color matching on both sides of a printed document when observed against thelight. To easily obtain a color matching, whatever the colors that are aimed for, it is essential to have a model that helps in calculating the quantity of ink to be left on the document. A model must be used to predict the spectral reflectance and the transmittance factors of the printed document by describing the phenomena of optical diffusion really present in the ink layers and in the document. We shall focus our interest especially on translucent printed documents that have halftone colors on both sides. Our goal here is to predict the visual rendering in different configurations of observation. To that end, we are offering a new approach based on the use of flux transfer matrices to predict the spectral reflectance and transmittance factors of prints when they are simultaneously lit up on both sides. By representing with transfer matrices the optical behavior of the different components present in a printed document, we see that the description of flux transfer between these elements is thus simplified. This mathematical framework leads to the construction of prediction models of halftone printed colors on diffusing materials. We also show that some existing models, such as the Kubelka-Munk or the Clapper-Yule models, can also be formulated in transfer matrices terms. The results that we get with the models used in this work make apparent identical prediction quality and in some cases even better ones to the ones found in the state of the art, while offering a simplification of the mathematical formulation and the physical description of the flux transfer. This simplification thus transforms these models into calculation tools that can easily be used especially for the choice of quantities of ink that must be left on both sides of the document in order to obtain color matching
Document type :
Theses
Complete list of metadatas

Cited literature [100 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-02017776
Contributor : Abes Star :  Contact
Submitted on : Wednesday, February 13, 2019 - 1:02:06 PM
Last modification on : Monday, January 13, 2020 - 5:46:07 PM
Long-term archiving on: : Tuesday, May 14, 2019 - 6:32:45 PM

File

These-MAZAURIC-Serge-2016.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-02017776, version 1

Citation

Serge Mazauric. Modèles spectraux à transferts de flux appliqués à la prédiction de couleurs sur des surfaces imprimées en demi-ton. Optique / photonique. Université de Lyon, 2016. Français. ⟨NNT : 2016LYSES064⟩. ⟨tel-02017776⟩

Share

Metrics

Record views

221

Files downloads

115