Predicting Spectral Halftone Measurements for Different Instruments Using a New Multi-Scale Approach
März 2008
Dieses Jahr findet wieder eine CGIV statt. Zusammen mit M. Sormaz, S. Mourad und P. Jenny habe ich an diesem Paper gearbeitet, das am 10. Juni in Barcelona präsentiert wird.
Abstract
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.
Subsurface Scattering Effects in Halftoning
April 2007
Meine Masterarbeit zum MSc ETH CS behandelt den Effekt, dass beim Bedrucken von Papier Bilder dunkler erscheinen, als sie tatsächlich sein sollten. Ende April 2007 wurde diese Arbeit fertiggestellt. Die schriftliche Arbeit kann hier als PDF heruntergeladen werden.
Computing Light Statistics in Heterogeneous Media Based on a Mass Weighted Probability Density Function (PDF) method
Februar 2007
Während des Jahres 2006 bearbeitete ich zusammen mit P. Jenny, S. Mourad, M. Vöge und K. Simon ein Paper welches im Februar des Jahres 2007 von JOSA akzeptiert und am 11. Juli 2007 publiziert wurde. Das Paper ist erhältlich im JOSA A, Vol. 24, Issue 8, pp. 2206-2219.
Abstract
Based on the transport theory, we present a modeling approach to light scattering in turbid material. It uses an efficient and general statistical description of the material's scattering and absorption behavior. The model estimates the spatial distribution of intensity and the flow direction of radiation, both of which are required, e.g., for adaptable predictions of the appearance of colors in halftone prints. This is achieved by employing a computational particle method, which solves a model equation for the probability density function of photon positions and propagation directions. In this framework, each computational particle represents a finite probability of finding a photon in a corresponding state, including properties like wavelength. Model evaluations and verifications conclude the discussion.
Modeling Light Scattering in Paper for Halftone Print
Juni 2006
An der European Conference on Color in Graphics, Imaging and Vision
CGIV war ich dieses Jahr vertreten mittels eines Conference-Papers, erstellt in Zusammenarbeit mit P. Jenny, M. Vöge (Vortragender) und S. Mourad.