打印复印文件朱墨时序表观特征初探

本文详细介绍了一案例的检验过程,并通过简单实验对激光打印、静电复印形成文件的朱墨时序的表观特征进行了粗浅的探究。总体而言,两种时序在朱墨交叉点的表观特征上具有文字与印文均完整、肉眼感觉文字均压在印文之上的共同点;在两者本质的差异点上,先朱后墨表现为交叉点的墨粉与未交叉部位一致,先墨后朱表现为交叉点的墨粉光泽度增加、具有潮湿感、以及易出现水珠状的印油积聚现象。     

对利用计算机图像处理技术伪变造文件的检验

在计算机图像处理技术用于文件检验工作的同时,也被一些犯罪分子所利用。文章阐述了利用计算机图像处理技术伪变造文件的手段、特点及对其进行检验的方法,以期对该类文件的检验工作有所裨益。     

自动消色笔书写笔迹显现方法的实验研究

目的为自动消色笔书写笔迹的显现识别提供最佳方法。方法通过观察不同种类的自动消色笔书写在不同纸张上,保存在不同环境下的笔迹的消色过程、消色时间,分析判断消色笔书写笔迹的基本特性。使用文检仪、静电压痕仪、不同浓度的氢氧化钠溶液显现消色笔迹,比较不同显现识别方法的特点及优劣。结果不同的显现方法各有优劣,使用氢氧化钠溶液显色效果的最佳浓度为1.0 mol。结论在自动消色笔书写笔迹的显现中,可以根据不同情况,选择合适的显现方法达到识别检验的目的。     

光谱成像检验法在朱墨时序鉴定中的应用

光敏印文色料与签字笔书写色料交叉重叠后,因互溶渗透不易形成层状结构而使判定朱墨时序的难度较大。光谱成像检验法是通过比较交叉点、纯印文色料、纯墨迹色料处的反射曲线位置来判定交叉时序关系。     

从体育邮票的发行状况看新中国60年体育发展轨迹

从新中国60年体育邮票发行的种类、数量、套数、内容等进行统计和分析发现，体育邮票的发行受到一定时期的政治、经济、文化科学等因素的影响和制约。体育邮票发行状况所划分的三个阶段与《当代中国体育》对新中国体育发展所划分的四个阶段基本上是一致的，从而证明了对某一时期体育邮票的发行状况进行分析，也是探寻新中国体育发展轨迹的一种方法，其目的是为了加深对新中国体育发展进程及其规律的认识。     

印文鉴定相关问题探讨——高仿真印文鉴定

当前,与印文鉴定相关的并在鉴定实践中经常遇到的新问题和难点问题有高仿真印文的鉴定、变造印章问题、利用真实印文变造文件、同版印章印文、朱墨时序等,本文就高仿真印文的鉴定进行了系统阐述,介绍了各种高仿真印文,包括各种高仿真印章的盖印印文、复制印文、转印印文的伪造手段及其特点,并提出了高仿真印文的鉴定思路和要点。     

签字笔水、圆珠笔油红外发光特性的研究

目的记录不同激发光、接收滤光镜下,各种油墨红外发光强弱的程度,为文字检验提供基础性的研究。方法用多波段光源中510~650nm单色光激发各种油墨样本,全波段物证检验CCD系统记录样本在530~950nm接收滤光镜下出现的红外发光图像。结果多数油墨在接收滤光镜到达800~850nm时,呈现出强烈的红外发光状态,并随接收波段的上升而开始衰减。结论可利用某些油墨的发光与否,发光强与弱的特性,检验案件中涂改和涂抹字迹。     

Color Separation in Forensic Image Processing Using Interactive Differential Evolution

Color separation is an image processing technique that has often been used in forensic applications to differentiate among variant colors and to remove unwanted image interference. This process can reveal important information such as covered text or fingerprints in forensic investigation procedures. However, several limitations prevent users from selecting the appropriate parameters pertaining to the desired and undesired colors. This study proposes the hybridization of an interactive differential evolution (IDE) and a color separation technique that no longer requires users to guess required control parameters. The IDE algorithm optimizes these parameters in an interactive manner by utilizing human visual judgment to uncover desired objects. A comprehensive experimental verification has been conducted on various sample test images, including heavily obscured texts, texts with subtle color variations, and fingerprint smudges. The advantage of IDE is apparent as it effectively optimizes the color separation parameters at a level indiscernible to the naked eyes.     

Color separation in forensic image processing

In forensic image processing, it is often important to be able to separate a feature from an interfering background or foreground, or to demonstrate colors within an image to be different from each other. In this study, a color deconvolution algorithm that could accomplish this task is described, and it is applied to color separation problems in document and fingerprint examination. Subtle color differences (sometimes invisible to the naked eye) are found to be sufficient, which is demonstrated successfully for several cases where color differences were shown to exist, or where colors were removed from the foreground or background. The software is available for free in the form of an Adobe Photoshop-compatible plug-in.     

An evaluation of matching unknown writing inks with the United States International Ink Library

Utilizing a database of standards for forensic casework is a valuable resource. Undoubtedly, as more standards (and corresponding information about the specimens) are collected, there is a greater certainty of identification when a questioned and a known item cannot be distinguished after a series of analyses. The United States Secret Service and the Internal Revenue Service National Forensic Laboratory jointly maintain the largest known forensic collection of writing inks in the world, which is comprised of over 8500 ink standards collected worldwide, dating back to the 1920s. This study was conducted to evaluate the reliability of matching arbitrarily purchased pens with known inks from a database. One hundred pens were randomly obtained from a variety of sources and their respective ink compositions were compared with standards. Eighty-five of the inks were determined to be suitable for comparison utilizing optical examinations and thin-layer chromatography. Three of the inks did not match any of the specimens on record; one of these inks was similar to an ink from an identical brand of pen that was in the database, but had a modified formulation.