【作者】 李举；

【导师】 周世生；

【作者基本信息】 西安理工大学 ， 制浆造纸工程， 2006， 硕士

【摘要】 本文主要研究建立调频加网工艺条件下的三色呈色与分色配色数学模型,也就是建立调频加网工艺的色彩转换模型。虽然现有的彩色印刷的数学模型很多,然而专门针对调频加网工艺的色彩转换数学模型,国内外在这方面的研究较少。本文通过分析现有印刷颜色转换的数学模型,(1)针对典型的CTP胶印调频加网工艺条件,采用n值修正的局部纽介堡方程与三维查找表法分别建立从设备相关色空间CMY到设备无关色空间CIEXYZ或CIELab的色空间转换模型。对比、分析、验证这两种数学模型对调频加网工艺的理论适用性与实际应用性。深入分析影响调频加网的呈色模型精度的主要因素,尤其讨论了调频加网工艺的网点扩大问题,提出具有参考价值的调频加网有效网点面积率计算公式。(2)在此基础上,根据建立的n值修正的局部纽介堡方程,利用最优化法的序列二次规划法(SQP法)求解建立它的CIEXYZ色空间到CMY色空间色彩转换模型。(3)之后,讨论了三维查找表法在建立CIELAB色空间到CMY色空间色彩转换模型方面存在的问题;提出引入Delaunay四面体网格剖分技术,不仅成功的解决了设备色域范围的确定问题,而且解决三维查表插值法的分区问题。同时,优化其查找算法,提高了三维查找表法的搜索效率。最后,分别验证反向求解n值修正的局部纽介堡方程算法与Delaunay分割-四面体插值算法的模型精度,取得良好的建模效果。上述技术对于研究调频工艺的数据化、规范化以及色彩管理系统的进一步研究具有重要的参考价值与理论意义,同时在生产实际中,提高配色效率、降低配色误差,保证原稿色彩的精确复制等方面具有重要的实用价值。更多还原

【Abstract】 This paper mainly discusses the problem about how to establish color conversion model of FM halftoning technique between the device-independent color space CIELAB or XYZ and the device-dependent color space CMY .Although there are many color conversion models , the research of color conversion about FM halftoning technique is scarcely any.Above all, through analyzing the existed color conversion models and taking into account characteristic of FM halftoning techniques, this paper established the forward model which transformed the color from the color space CMY to the color space CIELAB or XYZ ,using the Yule-Nielsen Cellular Neugebauer equation and three-dimensioned look-up-table with tetrahedron interpolation technology. Compared , analyzed and tested them to find out whether this two algorithmic methods are adaptive and practicality. discussed the factors that influencing accuracy of the algorithmic methods ,especially dot gain problem of FM halftoning techniques . Then , author introduced a new area effectively covered equation which using the regression. Next, the performance of nonlinear optimization-routine algorithms were evaluated for their ability to efficiently invert the Yule-Nielsen Cellular Neugebauer model; After that, consider the problem of sample points distributing irregularly in the color space CIELAB , author brings forward the method that uses a 3D triangulation technique to build a tetrahedral partition of the printer color gamut volume enclosing the definition domain. The characterization provides the inverse transformation from the device-independent color space CIELAB to the device-dependent color space CMY, taking into account both colorimetric properties of the printer, and color gamut mapping . Finally, its accuracy tested throughout the colorant space. It was found to be highly accurate, performing as well as a more complex local, cellular Neugebauer equation. But its’speed of calculation was so fast that it is more easily to put into practice.The technology of color conversion has an direct effect on the capacity of color reproduction . The paper is of great value to the further research on the ICC-based CMS and has certain applied values in the publishing field, which helps to the standardization of FM halftoning printing technology .更多还原