基于网点结构形态的图像信息印刷复制研究

【作者】 王琪；

【导师】 周小凡；

【作者基本信息】 南京林业大学 ， 制浆造纸工程， 2013， 博士

【摘要】 网点是图像复制的基础单元，控制网点在印刷复制过程中线性传递是一种理想的印刷品质量控制方法。相对其它各类以信息真实准确再现和信息量精彩还原为目标的质控技术，它可以通过研究网点的复制特性来实现从根本上提高印刷品质量的目的。本论文着重研究网点微观结构特性与图像信息印刷复制相关性，从微观元素这一基础层面解决图像颜色信息再现的问题，在消费者对信息质量要求不断提升的背景下具有现实意义。论文考察了网点微观特征对宏观图像再现的影响，研究发现网点形态结构的差异会对印刷特性产生明显的影响，于是从网点微观结构形态入手，从三个方面对网点特性与印刷复制相关性进行了研究。第一，对印刷网点平面及立体形态进行表征与解析，研究网点微观形态参数的准确提取方法，以获得能对印刷质量进行评价的量化数据；第二，自主设计能快速准确评价网点混合呈色效果的测控条，并根据调幅、调频、同心圆网点反射率特性的差异，建立了不同形态网点的半色调呈色数学模型；第三，揭示了同心圆网点高饱和度色彩再现的机理，并对基于纽介堡方程的同心圆网点呈色模型进行了修正。在以上研究成果的基础上，设计多种网点半色调函数，实现多形态网点再现与输出，并对自定义数字网点质量进行评价，为网点形态优化提供了理论依据。论文首次研究了准确提取聚集态网点微观特征参数的方法,为了确定图像分析法所得到的网点形态参数的准确值，考虑印版网点补偿参数，研究并量化网点传递过程中的机械扩大和光学扩大，结果表明图像分析法得到的网点微观参数只包括网点机械扩大的属性，且最大类间方差法与迭代法是聚集态图像网点分割的准确算法。论文首次根据网点内部结构的差异建立了基于网点微观结构的反射率色彩预测模型，通过实验验证了同心圆网点反射率模型的准确性。论文还应用Clapper-Yule颜色预测模型和Lambert-Beer法则，引入光程理论，揭示了同心圆网点高饱和度色彩再现的机理，结果表明，同心圆网点的内部结构是其高饱和度色彩再现的主要原因。本论文的研究成果对于丰富印刷复制的研究内涵，探索新的网点结构形态，满足墨点保真复制的需求，指导并优化阶调与色彩复制方案有着重要的意义；研究成果在印刷、包装、数字媒体等产业中可得有效的应用。更多还原

【Abstract】 The dot is the basis unit of the image reproduction. In the process of printingreproduction，the dot can be controlled with linear transfer which is an ideal method incontrolling the quality of prints. By comparing with other quality control technologies aiming attrue and accurate reproduction and the perfect reproduction of the information content, this canimprove the quality of prints fundamentally by researching dot reproduction feature. Thisdissertation focuses on relevance between the dot microstructure feature and the imageinformation reproduction. It also solves the problem of image color information reproductionbased on the micro elements, thus it has practical significance on the background of increasingconsumers’ demands about the information quality.This dissertation investigates the influence of dot microstructure feature on macro imagereproduction and then the research shows that differences in the dot structure form have aneffect on the printing feature obviously. Then the dissertation starts from dot microstructureform and researches on the relevance between the dot microstructure feature and the printingreproduction from three aspects. First of all, the dissertation represents and analyses the printingdot of2D and3D form and researches the accurate extraction method of dot microstructureparameters to gain the quantitative data about evaluating the printing quality. Besides, thisdissertation designs a control strip autonomously which can evaluate the coloring effect ofmixed dots quickly and accurately, considers the reflectance feature differences between AMdot, FM dot and concentric dot, and builds halftone colorific math model about different dotstructure. Last of all, we reveal the mechanism of high saturation color reproduction about theconcentric dot and correct concentric dot colorific model based on the Neugebauer equations.On the basis results of research above, this dissertation designs several dot halftone functionsand achieve polymorphic dot reproduction and output, then we evaluate the quality ofuser-defined dots. This paper provides a theoretical basis for optimizing the dot structure.This dissertation firstly researches the method of extracting the clustered-dot microscopicfeature parameters accurately. In order to ensure the exact value of dot shape parameters basedon the image analysis methods, the study considers dot compensation parameters of printingplate, researches and quantifies Physical Dot Gain and Optical Dot Gain in the process of dottransfer, and the results show that dot microcosmic parameters contain only the attribute ofPhysical Dot Gain. What’s more, the OTSU method and the iteration method are accuratealgorithms on clustered-dot segmentation. The dissertation firstly establishes a reflectance colorprediction model based on the dot microstructure according to the differences in the dot interiorstructure, and it validates the accuracy of reflectance model about the concentric dot throughexperiments. Besides, the dissertation applies the Clapper-Yule color prediction model andLambert-Beer law, introduces the theory of optical path and reveals the mechanism of highsaturation color reproduction about the concentric dot. The result indicates that the interior dotstructure of concentric circles is the major reason for high saturation color reproduction. The achievement of this dissertation has significant impacts on enriching the connotationof this research on printing reproduction, exploring new dot structure form, meeting therequirement of dot fidelity reproduction. Moreover it guides and optimizes the method of toneand color reproduction. In addition, the research result can find effective application in thefields of printing, packaging and digital media.更多还原