中国书画颜料颜色仿真与存储方法研究

在虚拟绘制中,基于Kubelka-Munk颜色光学理论,提出了一种中国书画颜料颜色仿真新方法,其主要思想是:根据颜料R/G/B三颜色通道的遮盖力(c)和单位厚度颜料在黑背景下的反射率(Rb)计算得到颜料各颜色通道吸收系数(K)和散射系数(S),通过K、S和宣纸反射率计算得到宣纸上有效厚度为d时颜料的反射率(Rd),根据该反射率与下一层颜料的K、S和d计算得到两层颜料合成时的反射率,依此类推得到多层颜料合成时的反射率,将该反射率转换成颜色亮度值(R,G,B),从而得到宣纸上多层颜料合成时的颜色(RGB).在此基础上提出一种颜色存储方法,通过存储宣纸上颜色(RGB)实现对绘制结果的实时存取和显示.所提方法已成功应用于基于力反馈技术的虚拟绘制系统中,较好地仿真了植物色与矿物色在颜色合成中的不同特征.

Research on color simulation and storage method of pigments of Chinese calligraphy and painting

In the virtual painting, based on the Kubelka-Munk color optical theory, a new color simulation method for pigments of Chinese calligraphy and painting is presented firstly. The primary idea includes: the absorption and scattering coefficients ( K and S ) for a pigment at R/G/B three color channels are calculated by giving the hiding power ( c ) of the pigment and the reflectance ( R b) of unit thickness of the pigment over a black background both at three color channels. Given K, S and effective thickness ( d ) for a pigment and the reflectance of rice paper, the reflectance ( R d ) of the pigment over the rice paper background are calculated. Given R d and K, S, d for the next pigmented layer, the mixing reflectance of the two pigmented layers is determined. In the same way, the mixing reflectance of several pigmented layers is calculated. Then, they can be transformed into color intensities ( R, G, B ), and the mixing color (RGB) of the several pigmented layers over rice paper background is determined. Secondly, a color storage method is introduced to access and display painting results in real time by storing the color (RGB) over rice paper background. Finally, the proposed methods are applied to the virtual painting system based on the force feedback technology. The different characteristics of vegetal pigments and mineral pigments in mixing process are simulated.