栅格特征在打印文件检验中的应用研究  

Applicability of Grid Features in Examination of Printed Documents

作　　者：许士国[1] 王虹[2] 姜峰 XU Shiguo;WANG Hong;JIANG Feng(Liaoning Provincial Public Security Department,Shenyang 110032,China;Key Laboratoryfor Document Inspection and Identifi cation,Criminal Investigation Police University of China,Shenyang 110035,China)

机构地区：[1]辽宁省公安厅,沈阳110032 [2]中国刑事警察学院,文件检验鉴定公安部重点实验室,沈阳110035

出　　处：《刑事技术》2022年第1期58-63,共6页Forensic Science and Technology

基　　金：文件检验鉴定公安部重点实验室课题(KFKT1801)。

摘　　要：目的通过对打印文字栅格特征进行实验研究,总结其稳定性和易引起特征变化的因素,为二次添加打印和换页变造文件检验探索新的思路。方法以500个常用汉字为主要研究对象,选用不同品牌、不同型号激光打印机,设置不同分辨率或质量模式,用同一台电脑或不同台电脑安装不同驱动程序,打印中易宋体常用字不同字号的样本。通过对打印文字笔画细节特征进行比对分析,总结打印文字栅格特征的规律特点。结果打印文字存在三类栅格特征,一是横笔段厚度特征,二是竖笔段宽度特征,三是斜笔画阶梯特征。同一台打印机一次打印的文件,相同字体字号文字的栅格特征反映相同;不同打印机或同一台打印机连接不同版本操作系统的电脑,或安装不同驱动程序,或选择不同的打印分辨率,栅格特征可能发生变化。结论栅格特征在同一次打印的文件中具有稳定性,在不同硬件和软件环境下可能发生改变,可以为换页文件和二次添加打印文件检验提供新的思路。Objective It is difficult for forensic document examination to target second added printed and/or page-replaced documents from the model-identical and even same printer.The commonly-used printing devices(those types of needle,ink-jet or laser,all only able to process bitmap format files)cannot genuinely output the file of curving-glyph Chinese words.Alternatively,they adopt RIP(raster image processor)to handle the printed document,dividing every printed area further into certain numerous square zones(grid spaces)where to have the curving glyphs mapped so as to engender a printable bitmap format file.Here,grid features were to experimentally explore about their stability and change-caused factors with the printed documents,for purpose to provide a new reference regarding to identification of second added printed and/or page-replaced documents.Methods 500 frequently-used Chinese characters were taken as sample to print into their 9 pt,10.5 pt,12 pt,14 pt,15 pt,16 pt and 18 pt Simsun fonts with 26 laser printers of different brands or models at discrepant resolutions or quality modes.The laser printers were controlled under various print-driver programs from the same or different computers.With comparative analysis into the specifics of those printed words’strokes,the involving grid features were to summarize their patterns and traits.Results There are 3 kinds of grid features:TFHS(Thickness Feature of Horizontal Strokes),WFVS(Width Feature of the Vertical Strokes)and LFOS(Ladder Feature of Oblique Strokes).The same-one printer delivered identical grid features when it printed one document to produce the words of same font and size from an undisturbed same-time printing.The grid features may change with the various printers,the computer-operation systems,the print-driver programs and/or the printing resolutions.Conclusions The grid features are stable within one document that is printed from a printer at one time,yet leaving a probability of changing once the printing configuration(hardware/software)has got any di

关 键 词：文件检验 二次添加打印 打印机驱动程序 栅格特征 光栅图像处理器 

分 类 号：D918.92[政治法律—法学]