颜色设备相关性的特点导致地图在跨媒介再现时容易出现丢色、偏色等现象,影响地图视觉效果,甚至传输错误的属性、数量等信息。从地图色域特征出发,将地图色域映射问题转换为目标设备色域约束下的地图色域离散点云形变问题。进一步引入Delaunay剖分和几何矩,定义CIE1976LAB色空间下地图色域形变的目标函数,给出全局最优解的求解流程。将算法结果与ICC再现意图结果进行对比,结果表明该方法能够很好保持地图整体的色貌特征以及局部图斑之间的色彩对比、连续等色彩特征,能够显著提高地图跨媒介地图颜色复制精度。
The chromogenic abilities of different map-carrying media are from strikingly divergent coloring mechanisms,physical properties and application conditions.During the cross media map transmission,some accidental phenomena like color-lost and color-cast may occur due to device dependence.This might affect the visual effects of maps,or even lead to false property,quantity and the level information.Based on the geometrical characteristic analysis on map gamut,the issue of gamut mapping can be transformed into the deformation problem of color gamut point cloud under color gamut constraints of target devices.Furthermore,the methods of Delaunay subdivision and geometric moments are introduced,and the objective function of map color gamut deformation under CIE1976LAB color space is defined.Then,the solving strategy of a global optimal solution is given.By comparing the algorithm's output with ICC rendering intent,the solution given by this paper is proved to be able to maintain the overall color appearance of maps,as well as the color contrast,continuity between local map spots,and to have achieved the accurate cross media map transmission and reproduction.