Mathieu Hébert

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We propose a spectral prediction model for predicting the reflectance and transmittance of recto-verso halftone prints. A recto-verso halftone print is modeled as a diffusing substrate surrounded by two inked interfaces in contact with air (or with another medium). The interaction of light with the print comprises three components: (a) the attenuation of(More)
We propose a compositional model for predicting the reflectance and the transmittance of multilayer specimens composed of layers having possibly distinct refractive indices. The model relies on the laws of geometrical optics and on a description of the multiple reflection-transmission of light between the different layers and interfaces. The highly complex(More)
The transmittance spectrum of halftone prints on paper is predicted thanks to a model inspired by the Yule-Nielsen modified spectral Neugebauer model used for reflectance predictions. This model is well adapted for strongly scattering printing supports and applicable to recto-verso prints. Model parameters are obtained by a few transmittance measurements of(More)
The present paper investigates the reflection and transmission properties of piles of nonscattering sheets. Using a spectral prediction model, we perform a detailed analysis of the spectral and color variations induced by variations of the number of superposed sheets, the absorbance of the sheet material, the refractive index of the medium between the(More)
We extend a previously proposed spectral reflectance and transmittance prediction model for recto-verso prints to the case of multi-ink halftones. The model takes into account the multiple reflections and the lateral propagation of light within the paper substrate (optical dot gain) as well as the spreading of the inks according to their superposition(More)
We review the phenomena having an impact on the interaction between light, paper and color halftones. They comprise surface reflections and refractions at the air-paper interface, propagation of light within the paper, internal reflections at the paper-air interface, as well as ink spreading and trapping. We introduce basic notions from radiometry and(More)
Spectral prediction models for halftone prints generally assume homogeneously thick and sharply edged ink dots, i.e., bilevel halftones. In real prints, the ink thickness often decreases at the boundaries of the ink dots, thereby forming continuous-level halftones. The present study aims at verifying to what extent the classical Clapper-Yule and(More)
We propose a model for predicting the reflectance and transmittance of multiple stacked nonscattering coloring layers that have different refractive indices. The model relies on the modeling of the reflectance and transmittance of a bounded coloring layer, i.e., a coloring layer and its two interfaces with neighboring media of different refractive indices.(More)
Reliable color reproduction can be achieved by establishing, using a model, the correspondence between the spectral reflectance of the printed surface and the amounts of deposited inks. In this paper, we review the main models proposed in the literature, recall how each one is calibrated and compare their prediction accuracy for several print sets. The(More)