基于数字印前流程的模拟印刷系统的研究与开发
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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。
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.
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。
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.
引文
[1]高峰.现代印前技术的发展流程[J].广东印刷,2004,3：64,65.
[2]贾文华.CTP技术的核心[J].电子出版,2000,2：16,17.
[3]张占超.RIP是如何工作的[J].电子出版,2002,3：22-24.
[4]何京.为生产选择正确的RIP[J].电子出版,2003,3：51-53.
[5]宗义刚.印前数字化工作流程在国内外应用状况的对比分析[J].今日印刷,2006,2：2,3.
[6]褚庭亮.印前数字、网络化在广东成效显著[J].印刷工业,2008,6：16,17.
[7]周世生.印刷色彩学[M].北京：印刷工业出版社,2005.
[8]田玉敏,梁若莹.计算机彩色输入输出设备常用颜色空间及其转换[J].计算机工程,2002,28(9)：22-24.
[9]Adrian Ford, Alan Roberts. Colour Space Conversions[DB/OL]. http://www.poynton.com /PDFs/coloureq.pdf,1998.
[10]古晶.RGB到Lab颜色空间转换[J].广东印刷,2009,5：11,12.
[11]宋宗明,色差公式的发展和最新CIE色差公式[J].纺织高校基础科学学报,1995,8(4)：344-346.
[12]李文元,黄翔东,李昌禄,袁亚斌,王兆华.伪彩色增强显示的设计与实现[J].中国体视学与图像分析,2003(12)：235-239.
[13]蓝春生,蓝鹏,曹煜媛.医学图像的伪彩色处理[J].中国体视学与图像分析,2002(9)：166-169
[14]贺兵,刘扬.模块化设计在包装机械设计中的应用[J].包装工程,2008,29(10)：140-141.
[15]姚江.模块化设计方法在信息产品设计中的应用[J].科技情报开发与经济,2008,18(11)：99-100.
[16]Adobe System Incorporated, PostScript(?) 3rd Edition [EB/OL]. http://www.adobe.com /devnet/postscript/pdfs/PLRM.pdf,1999.
[17]Adobe System Incorporated, PDF Reference sixth edition [EB/OL]. http://www.adobe.com /devnet/acrobat/pdfs/pdf_reference_1-7.pdf,2006.
[18]Adobe System Incorporated, TIFF6[EB/OL]. http://partners.adobe.com/public/developer/en/tiff/ TIFF6.pdf,2006.
[19]吴云天,陈永常.TIFF格式在设计与印刷中的作用[J].包装工程,2005,26(5)：223-224.
[20]孙中胜,顾桓.CMYK图像的TIFF格式[J].电子工程师,2006,32(1)：43.
[21]刘武辉,吴莺,张建华.数字印前技术[M].北京：化学工业出版社,2008：88-89.
[22]刘全香.印刷图文复制原理与工艺[M].北京：印刷工业出版社,2008：49.
[23]田全慧,刘珊.印刷色彩管理[M].北京：印刷工业出版社.2007：19-27.
[24]曹从军.色彩管理关键技术CIE L*a*b*与CMYK变换算法的研究[D].西安：西北大学,2008.
[25]任小玲,张二虎.数字半色调技术发展概述[J].西安工业学院学报,2003,23(2)：109-113.
[26]宣柱香.国外调频加网发展历史概要[J].印刷杂志,1998,04：51.
[27]夏雪.数字加网的新趋势混合加网[J].广东印刷,2008,06：19-20.
[28]高珊珊,宋晓明.混合网点加网技术解析[J].数码印刷,2008,5：42,43.
[29]Isaac Amidror, Roger D. Hersch. Neugebauer and Demichel:Dependence and Independence in n-Screen Superpositions for Colour Printing[J].Color Research and Application,2000,25(4): 273-277.
[30]Mario Rotea, Carlos Lana, Daniel Viassolo. Robust Estimation Algorithm for Spectral Neugebauer Models[J]. Maui:Proceedings of the 42nd IEEE Conference on Decision and Control[R], December 2003:4114
[31]芦宁.色彩方程在印刷包装中应用的研究[D].西安：西安理工大学,2004：65-66.
[32]李艳莉,冯再荣.基于纽介堡方程的专色油墨调配[J].印刷质量与标准化,2008,05：61-62.
[33]张琳,杨旭.纽介堡方程计算精度的研究[J].包装工程,2007,28(11)：73-74.
[34]郑元林,杨淑蕙,周世生,曹从军.CIE 1976LAB色差公式的均匀性研究[J].包装工程,2005,26(2)：63—65.
[35]李勤.CIELAB之后色差公式的新进展[J].染料工业,1997,34(3)：31-35.
[36]郑元林,杨淑蕙,周世生,戚永红.色差公式CMC(1：c)、CIE94和CIEDE2000的对比研究[J].包装工程,2006,27(5)：127-128.
[37]陈炳萍,唐正宁.CIEDE2000色差公式的研究[J].包装工程,2006,27(3)：67-69.
[38]郑元林,刘士伟.最新色差公式：CIEDE2000[J].印刷质量与标准化,2004,7：34-36.
[39]Gaurav Sharma, Wencheng Wu, Edul N.Dalal. The CIEDE2000 Color-Difference Formula: Implementation Notes, Supplementary Test Data, and Mathematical Observations[J]. Color Research and Application, Feb 2004,09:9.
[40]Lidija Mandic, Sonja Grgic, Mislav Grgic. Comparison of Color Difference Equations[R]. Croatia:48th International Symposium ELMAR-2006, June 2006:110.
[41]梁炯.印刷中的标准观察条件[J].印刷杂志,1999,10：32.
[42]全国印刷标准化技术委员会.常用印刷标准汇编[M].北京：中国标准出版社,2004：5.
[43]樊正复,马新民.概率论与数理统计[M].北京：机械工业出版社,2004：38.
[44]汪荣鑫.数理统计[M].西安：西安交通大学出版社,2006.60-61.
[45]汪孔桥,沈兰荪,邢昕.一种基于视觉兴趣性的图象质量评价方法[J].中国图象图形学报,2000,5(4)：301.
[46]北京九州恒润科技有限公司.Matlab系列产品特点及优势[J].软件世界,2006,9：68-69.
[47]李显宏.精通Matlab图像处理[M].北京：电子工业出版社,2006.
[48]李显宏.Matlab 7.x界面设计与编译技巧[M].北京：电子工业出版社,2006.
[2]贾文华.CTP技术的核心[J].电子出版,2000,2：16,17.
[3]张占超.RIP是如何工作的[J].电子出版,2002,3：22-24.
[4]何京.为生产选择正确的RIP[J].电子出版,2003,3：51-53.
[5]宗义刚.印前数字化工作流程在国内外应用状况的对比分析[J].今日印刷,2006,2：2,3.
[6]褚庭亮.印前数字、网络化在广东成效显著[J].印刷工业,2008,6：16,17.
[7]周世生.印刷色彩学[M].北京：印刷工业出版社,2005.
[8]田玉敏,梁若莹.计算机彩色输入输出设备常用颜色空间及其转换[J].计算机工程,2002,28(9)：22-24.
[9]Adrian Ford, Alan Roberts. Colour Space Conversions[DB/OL]. http://www.poynton.com /PDFs/coloureq.pdf,1998.
[10]古晶.RGB到Lab颜色空间转换[J].广东印刷,2009,5：11,12.
[11]宋宗明,色差公式的发展和最新CIE色差公式[J].纺织高校基础科学学报,1995,8(4)：344-346.
[12]李文元,黄翔东,李昌禄,袁亚斌,王兆华.伪彩色增强显示的设计与实现[J].中国体视学与图像分析,2003(12)：235-239.
[13]蓝春生,蓝鹏,曹煜媛.医学图像的伪彩色处理[J].中国体视学与图像分析,2002(9)：166-169
[14]贺兵,刘扬.模块化设计在包装机械设计中的应用[J].包装工程,2008,29(10)：140-141.
[15]姚江.模块化设计方法在信息产品设计中的应用[J].科技情报开发与经济,2008,18(11)：99-100.
[16]Adobe System Incorporated, PostScript(?) 3rd Edition [EB/OL]. http://www.adobe.com /devnet/postscript/pdfs/PLRM.pdf,1999.
[17]Adobe System Incorporated, PDF Reference sixth edition [EB/OL]. http://www.adobe.com /devnet/acrobat/pdfs/pdf_reference_1-7.pdf,2006.
[18]Adobe System Incorporated, TIFF6[EB/OL]. http://partners.adobe.com/public/developer/en/tiff/ TIFF6.pdf,2006.
[19]吴云天,陈永常.TIFF格式在设计与印刷中的作用[J].包装工程,2005,26(5)：223-224.
[20]孙中胜,顾桓.CMYK图像的TIFF格式[J].电子工程师,2006,32(1)：43.
[21]刘武辉,吴莺,张建华.数字印前技术[M].北京：化学工业出版社,2008：88-89.
[22]刘全香.印刷图文复制原理与工艺[M].北京：印刷工业出版社,2008：49.
[23]田全慧,刘珊.印刷色彩管理[M].北京：印刷工业出版社.2007：19-27.
[24]曹从军.色彩管理关键技术CIE L*a*b*与CMYK变换算法的研究[D].西安：西北大学,2008.
[25]任小玲,张二虎.数字半色调技术发展概述[J].西安工业学院学报,2003,23(2)：109-113.
[26]宣柱香.国外调频加网发展历史概要[J].印刷杂志,1998,04：51.
[27]夏雪.数字加网的新趋势混合加网[J].广东印刷,2008,06：19-20.
[28]高珊珊,宋晓明.混合网点加网技术解析[J].数码印刷,2008,5：42,43.
[29]Isaac Amidror, Roger D. Hersch. Neugebauer and Demichel:Dependence and Independence in n-Screen Superpositions for Colour Printing[J].Color Research and Application,2000,25(4): 273-277.
[30]Mario Rotea, Carlos Lana, Daniel Viassolo. Robust Estimation Algorithm for Spectral Neugebauer Models[J]. Maui:Proceedings of the 42nd IEEE Conference on Decision and Control[R], December 2003:4114
[31]芦宁.色彩方程在印刷包装中应用的研究[D].西安：西安理工大学,2004：65-66.
[32]李艳莉,冯再荣.基于纽介堡方程的专色油墨调配[J].印刷质量与标准化,2008,05：61-62.
[33]张琳,杨旭.纽介堡方程计算精度的研究[J].包装工程,2007,28(11)：73-74.
[34]郑元林,杨淑蕙,周世生,曹从军.CIE 1976LAB色差公式的均匀性研究[J].包装工程,2005,26(2)：63—65.
[35]李勤.CIELAB之后色差公式的新进展[J].染料工业,1997,34(3)：31-35.
[36]郑元林,杨淑蕙,周世生,戚永红.色差公式CMC(1：c)、CIE94和CIEDE2000的对比研究[J].包装工程,2006,27(5)：127-128.
[37]陈炳萍,唐正宁.CIEDE2000色差公式的研究[J].包装工程,2006,27(3)：67-69.
[38]郑元林,刘士伟.最新色差公式：CIEDE2000[J].印刷质量与标准化,2004,7：34-36.
[39]Gaurav Sharma, Wencheng Wu, Edul N.Dalal. The CIEDE2000 Color-Difference Formula: Implementation Notes, Supplementary Test Data, and Mathematical Observations[J]. Color Research and Application, Feb 2004,09:9.
[40]Lidija Mandic, Sonja Grgic, Mislav Grgic. Comparison of Color Difference Equations[R]. Croatia:48th International Symposium ELMAR-2006, June 2006:110.
[41]梁炯.印刷中的标准观察条件[J].印刷杂志,1999,10：32.
[42]全国印刷标准化技术委员会.常用印刷标准汇编[M].北京：中国标准出版社,2004：5.
[43]樊正复,马新民.概率论与数理统计[M].北京：机械工业出版社,2004：38.
[44]汪荣鑫.数理统计[M].西安：西安交通大学出版社,2006.60-61.
[45]汪孔桥,沈兰荪,邢昕.一种基于视觉兴趣性的图象质量评价方法[J].中国图象图形学报,2000,5(4)：301.
[46]北京九州恒润科技有限公司.Matlab系列产品特点及优势[J].软件世界,2006,9：68-69.
[47]李显宏.精通Matlab图像处理[M].北京：电子工业出版社,2006.
[48]李显宏.Matlab 7.x界面设计与编译技巧[M].北京：电子工业出版社,2006.