EMPA Media Technology

Publications 2005

Gamut Mapping for Small Destination Gamuts

P. Zolliker, M. D├Ątwyler, K. Simon

In this paper we present a new approach to develop gamut mapping algorithms for small destination gamuts in particular newspaper printing. Gamut mapping algorithms have to satisfy the constraints of the destination gamut, preserving as much of the color appearance of the original image as possible. For small destination gamuts it is a special challenge to find a good compromise between conservation of color, lightness, saturation, and local contrast. This work focuses on two main points: One is the control of the local mapping properties in particular continuity and contrast conservation of the mapping. The second is the use of a large set of application relevant test images for the psychovisual tests in contrast to the usually small set of high quality test images.

AIC Colour 05 Oral Papers

Small Gamut

On the Continuity of Gamut Mapping Algorithms

P. Zolliker, M. D├Ątwyler, K. Simon

The design of a gamut mapping algorithm (GMA) is always a compromise between preserving different competing aspects such as color, contrast and lightness. A natural requirement to a GMA is that the algorithmic treatment of this competition has to avoid any additional artefacts such as discontinuities or loss of contrast. In this paper several common gamut mapping algorithms are studied from this aspect, resulting in the observation that problems with geometric discontinuities are widespread. For the assessment of the phenomena induced by local mapping properties, an algorithmic test was developed and applied. This new test supports both, the quality check of existing as well as the development of new GMAs. Finally we present a first new algorithm designed to have a good behavior concerning continuity and contrast conservation which also performs well in classical psychophysical tests.

Color imaging. Conference No10, San Jose CA , ETATS-UNIS (17/01/2005) 1988, vol. 5667, pp. 220-233, [Note(s) : XI, 624 p., ] (26 ref.) ISBN 0-8194-5640-3

Discontinuity in Gradients

Toward Image-dependent Gamut Mapping: Fast and Accurate Gamut Boundary Determination

J. Giesen, E. Schuberth, K. Simon, P. Zolliker

We propose a new geometric method to compute color gamut boundaries fast and geometrically accurate. The method is designed for high-quality image-dependent gamut mapping in three dimensions. For such a mapping the gamut boundary must be constructed for every image individually and we cannot rely on precomputed lookup tables. This can only be practical if the gamut boundary can be computed very fast. The proposed method is fast compared to other geometric methods without sacrificing geometric accuracy of the computed boundary.

Proc. IS&T/SPIE Symposium on Electronic Imaging (2005) 201-210

Determing the Boundary