A New Color Management System Based on Human Perception and its Application to Recording and Reproduction of Art Paintings

A new color management system has been developed for high definition color recording and reproduction of art paintings. This system is consisted of high accurate multiband camera, personal computer and projected type display. The multi-band camera is composed by five band filters and single chip CCD camera with 2048x2048 pixels. The reflectance spectra of each pixel of the object were estimated by using five band images within less than the average color difference ∆E*ab = 1.16. The spectral transmittance of five filters was determined by simulated annealing method and principal component analysis of spectral reflectance of paintings. Images of art paintings were reproduced onto the projection type monitor under the consideration of color appearance. In this paper, we describe methods to estimate of reflectance spectra of paintings from five band images, optimization of spectral transmittance of filters and color reproduction of paintings based on the color appearance models. Introduction In recent years, high accuracy digital color imaging system is required in artworks and medical imagings by the advent of information superhighway. In artworks, conventional photographic system has been used for image acquisition and recording. HDTV(High Definition Television) are also used for displaying the paintings, arts and crafts in several 16 Japanese museums. Photographic system, hybrid imaging system used film and scanner, and HDTV system only record the R,G,B three channel images, and they cannot record the reflection spectra of the objects. Reflection spectra is one of the most important information of the objects, and it is not dependent on the spectral radiant distribution of the taking light source. On the other hand, color reproduction of those imaging systems is based on the colorimetric color reproduction as to have same chromaticities between object and image. However, it should be considered the color reproduction based on the human perception such as color adaptation under the viewing condition in an art gallery or museum. We have developed the high accurate imaging systems which is consisted of image acquisition system used multiband CCD camera, color management system based on color adaptation model and estimation of reflection spectra of the objects, and display systems as shown in Figure 1. In the following sections, detail of the developed imaging systems is described. Multiband camera and the Estimation of Reflection Spectra In image acquisition, we used two high quality digital cameras; Fotex F-10 (2048x2048 pixels, 12 bits/pixel ) and Kodak DCS420m (1536x1024 pixels 12bits A/D, 8 bits output). Multiband images were captured by digital camera incorporating a rotating wheel comprising five color filters in front of camera lens. Gray scales with 16 steps and crop marks were recorded with object in each channel, and each channel image data was merged into single file.