EMPA Media Technology

Publications 2008

Modeling Interference Color on Surface Structured Fibers

P. Zolliker, S. Mourad, W Shi, M. Halbeisen, H. Schmidt

A model is presented to describe color effects based on interference on approximately periodic nano-structured surfaces. The model is verified with optical color measurements on surface structured textile fibers which strong iridescent color effects. Good agreement can be found for the diffracted spectra as well as on images of diffraction patterns. Furthermore we show simulations and comparisons of the color appearance of bundles of parallel fibers. This model can be used as a base for simulating color effects in textile tissues, allowing a characterization and optimization in terms of fiber cross section, structure period and type for different lighting conditions.

The 4th European Conference on Colour in Graphics, Imaging and Vision, Terrassa - Barcelona, España, June 2008.


Predicting Spectral Halftone Measurements for Different Instruments Using a New Multi-Scale Approach

M. Sormaz, S. Mourad, T. Stamm, P. Jenny

The objective of this work is to predict the deviations between spectral measurements obtained by different devices for halftone prints. The predictions are based on a known particle Monte Carlo method for light scattering in random media. Furthermore, the method supports optical interfaces between substrates of different indices of refraction.

In our studies we compare measurements of print patches captured with a hand-held (EyeOne) and a microscopic spectrophotometer. Varying illumination and capturing geometries throughout different measuring devices pose a challenge to accurately predict the measurement differences with numerical models. These geometries were determined and implemented as boundary conditions in the simulated domains. In this paper, we present first evaluations that demonstrate reasonable agreement with the experimental data.

Additionally, graphic wedge comprising ten halftone samples with ergodic, isotropic halftone patterns of different ink coverages has been considered. This is achieved by devising a complementary, multi-scale simulation level that allows to improve the computational time efficiency in order to deal with halftone samples of large numbers of dots.

The 4th European Conference on Colour in Graphics, Imaging and Vision, Terrassa - Barcelona, España, June 2008.


Farbe im Digitalen Publizieren

K. Simon

Der traditionelle CMYK-Workflow ist von einem operativen Umgang mit dem Thema Farbe gekennzeichnet. Diese Grundhaltung setzt voraus, dass der Einzelne weiss, was von ihm erwartet wird bzw. was die Anderen tun. Dies ist jedoch im Zeitalter des Cross Media Publishing mit komplexen, variablen, verteilten, datenbankgestützten Workflows massiv in Frage gestellt. Zusätzlich werden Berufsgruppen wie Autoren, Fotografen, Designer oder Informatiker immer stärker in die Publikationsprozesse involviert bzw. sind deren fachliche Abgrenzungen untereinander unklar. In diesem Szenario bietet das vorliegende Werk konzeptionelles Wissen zur aktiven Gestaltung der Arbeitsabläufe im Gesamtprozess der digitalen Farbwiedergabe.

Springer Verlag, ISBN 978-3-540-37327-8

Farbe im Digitalen Publizieren

Visualizing public transport networks: an experiment in Zurich

S. Avelar

Transportation has long been a sub ject of mapping. However, there is still very little guidance available to a mapmaker looking for guidelines on how to create properly a schematic map for showing routes of a public transport system. Creating an aesthetically pleasing and easily understandable cartographic representation of a public transport network for thousands or millions of passengers is a challenging task. The need for design strategies based on cartographic principles grows as many GIS practitioners use routes as a base for analysis and mapping. This paper gives a list of aspects to be considered in the visualization of a public transport network and presents two cartographic alternatives for depicting the transport network of the City of Zurich.

Journal of Maps, v2008, 134–150

Öffentlicher Verkehr Zürich

Color Design for Illustrative Visualization

L. Wang, J. Giesen, K. T. McDonnell, P. Zolliker, K. Mueller

Professional designers and artists are quite cognizant of the rules that guide the design of effective color palettes, from both aesthetic and attention-guiding points of view. In the field of visualization, however, the use of systematic rules embracing these aspects has received less attention. The situation is further complicated by the fact that visualization often uses semi-transparencies to reveal occluded objects, in which case the resulting color mixing effects add additional constraints to the choice of the color palette. Color design forms a crucial part in visual aesthetics. Thus, the consideration of these issues can be of great value in the emerging field of illustrative visualization. We describe a knowledge-based system that captures established color design rules into a comprehensive interactive framework, aimed to aid users in the selection of colors for scene objects and incorporating individual preferences, importance functions, and overall scene composition. Our framework also offers new knowledge and solutions for the mixing, ordering and choice of colors in the rendering of semi-transparent layers and surfaces. All design rules are evaluated via user studies, for which we extend the method of conjoint analysis to task-based testing scenarios. Our framework’s use of principles rooted in color design with application for the illustration of features in pre-classified data distinguishes it from existing systems which target the exploration of continuous-range density data via perceptual color maps.


Choice Based Conjoint Analysis: Discrete Choice Models vs. Direct Regression

B. Taneva, J. Giessen, P. Zolliker, K. Mueller

Conjoint analysis is family of techniques that originated in psychology and later became popular in market research. The main objective of conjoint analysis is to measure an individual’s or a population’s preferences on a class options that can be described by parameters and their levels. We consider preference data obtained in choice based conjoint analysis studies, where one observes test persons’ choices on small subsets of the options. There are many ways to analyze choice based con- joint analysis data. Here we want to compare two approaches, one based on statistical assumptions (discrete choice models) and a direct regres- sion approach. Our comparison on real and synthetic data indicates that the direct regression approach outperforms the discrete choice models.


Conjoint Analysis of Parametrized Gamut Mapping Algorithms

Z. Baranczuk, I. Sprow, P. Zolliker

We show that conjoint analysis, a popular multi-attribute preference assessment technique used in market research, is a well suited tool to simultaneously evaluate a multitude of gamut mapping algorithms with a psycho-visual testing load not much higher than in conventional psycho-visual tests of gamut mapping algorithms. The gamut mapping algorithms that we test using conjoint analysis are derived from a master algorithm by choosing different parameter settings. Simultaneously we can also test the influence of additional parameters like gamut size on the perceived quality of a mapping. Conjoint analysis allows us to quan- tify the contribution of every single parameter value to the perceived quality.

16th Color Imaging Conference Proceedings