## Theory of Combinatorial Algorithms

Prof. Emo Welzl and Prof. Bernd Gärtner

# Mittagsseminar (in cooperation with A. Steger, D. Steurer and B. Sudakov)

 Mittagsseminar Talk Information

Date and Time: Tuesday, February 01, 2005, 12:15 pm

Duration: This information is not available in the database

Location: This information is not available in the database

Speaker: Eva Schuberth

## What colors have to do with geometry: the gamut mapping project

The talk is about the problem of gamut mapping, which you are daily confronted with, probably without knowing it. It arises whenever colors are displayed or reproduced on some device (your monitor, your printer, etc.). This problem raises some geometric questions that we address in a project in collaboration with EMPA (Eidgenössisches Materialprüfungsamt/Swiss Federal Laboratories of Materials and Testing). A gamut is the entirety of colors that are contained in an image or that can be displayed by a device. Different devices usually have different gamuts, i.e. can display different sets of colors. A monitor for example usually can display more colors than a printer can print. This is why a transformation from the monitor's colors to the printer's colors has to be found.

A color can be seen as a point in a three dimensional color space. Thus a gamut is just a finite subset of R3 and a gamut mapping is a transformation between two subsets of R3. All existing gamut mapping algorithms use a contiuous description of gamuts, i.e they approximate gamuts with polyhedrons. Doing so one faces the following problems:

1. Surface reconstruction: given a finite subset of Rn, compute a polyhedron that captures the geometry of the subset. A crucial requirement is that the computation is done fast
2. Gamut mapping: Given two polyhedrons in Rn, find a transformation between them that fulfils a number of psycho-physical side conditions

In my talk I will point out, how we solved the first problem and what we plan to do to solve the second one.

Information for students and suggested topics for student talks