【作者】 韩啸；

【导师】 成刚虎；

【作者基本信息】 西安理工大学 ， 制浆造纸工程， 2010， 硕士

【摘要】 印刷产品的精细化需求越来越迫切,全方位研究印刷流程的误差产生根源和控制途径,提升印刷品质已成为业内研究热点。进入数字化时代以来,涌现了一系列的印前处理方法和系统。数字化印前处理流程存在着诸多系统误差,这些印前误差有的可以在印刷过程中通过参数调整进行补偿和控制,但有的却不能,或者很有限。开发模拟印刷系统,对于分析数字印前流程误差,进而进行后期补偿和调控,具有积极的方法论意义。基于此,本文在研究了数字印前流程的基础上开发实现了具有基本RIP功能的模拟系统,该系统不仅能对数字图像进行分色、加网处理,还能模拟理想条件下的印刷,对印刷效果做出大致预测。主要工作和取得的研究结论如下：1)分析印前流程的发展状况,研究数字印前系统,尤其是RIP系统的数据处理流程,在此基础上,对印前模拟系统进行了功能分析和模块分解。该系统共有图像读取与显示、RIP处理、模拟印刷与预视、色差分析、存储设置等五大模块。2)对色彩空间转换方法进行了分析研究,分别选择确定了系统中所采用的各种颜色空间转换方法,重点对CMYK颜色空间到RGB颜色空间的转换方法进行了研究分析,选择理论性较强、操作性更高的纽介堡方程作为转换的核心处理算法。3)基于纽介堡方程以实际色元面积率为依据,编程实现了系统的模拟印刷功能模块；以加网处理后的分色图像数字信息为依据,直接进行不同色版数据的叠合处理,实现了系统预视功能。这样用户可以分阶段的有选择的对模拟印刷效果进行预视。4)对常用的色差评价方法进行了研究分析,分别采用CIE 1976、CIE 1994、CIE 2000以及CMC(l:c)等色差公式,编程实现了系统的色差分析功能模块。该模块可以对模拟印刷图像与原数字图像之间的色差做出局部分析和整体评价分析。5)研究分析了数字印前系统常用的图像格式,确定了各工序数据格式及其存储方法,并基于Matlab平台,设计实现了对图像的读取、修改以及显示功能。6)使用Matlab中的GUI功能编程,设计了系统的人机界面。该界面易于操作,借助于它,操作人员可以根据需要对待印图像做出各种印前分析预览。更多还原

【Abstract】 The demands on refinement of printing products become more and more eilig, so comprehensive study on root of generation errors and control methods in the printing processes, and enhancement on printing quality have become a research hotspot in the industry. Since the world went into the digital age, a series of prepress processing methods and systems has appeared. Digital prepress process exists many systematic errors, and some errors can be compensated and controlled by parameters adjustment, some are impossible or limited. Developments on printing simulation system have positive methodological significance for analysis of digital prepress workflow errors, latter compensation and control. This paper develops and implements the simulation system with basic RIP functions based on study of digital prepress workflow. This system can not only implement color-separation and screening, but also simulates the printing under ideal conditions, and makes a general prediction for printing results. Main research work of this paper and obtained conclusions are as follow:1) Analyzed the development of prepress workflow, and studied on the digital prepress systems, particular data process-flow in RIP system. On this basis, the modules were be decomposed and functions were be analyzed. This system has five modules including read and display digital image, RIP processing, printing simulation and preview, analysis of color-difference, system-configure.2) Analyzed and studied color space conversion methods. Chose and confirmed color space conversion methods used in the system. Researched and analyzed color space conversion methods from CMYK to RGB, and selected Neugebauer equation as core algorithm with stronger theory and higher operability.3) Based on Neugebauer equation with the percentage of actual color element area, implemented function module of printing simulation by programming. Based on digital information of color-separation images after screening, superposed different plate’s data directly, and implemented system function of preview. User can preview the printing simulation efforts selectively by stages. 4) Researched and analyzed common evaluation methods of color-difference, and used color-difference equations of CIE1976, CIE1994, CIE2000 and CMC(l:c) respectively.5) Researched and analyzed common image formats in digital prepress system, and identified data formats and storage methods in each process. Implemented the function to read, modify and display the image.6) Programmed with GUI in Matlab, and designed the man-machine interface. The interface is easy to use, and operator can analyze and preview the image which will be printed according to demands.更多还原