On the discriminability of the handwriting of twins

As handwriting is influenced by physiology, training, and other behavioral factors, a study of the handwriting of twins can shed light on the individuality of handwriting. This paper describes the methodology and results of such a study where handwriting samples of twins were compared by an automatic handwriting verification system. The results complement that of a previous study where a diverse population was used. The present study involves samples of 206 pairs of twins, where each sample consisted of a page of handwriting. The verification task was to determine whether two half-page documents (where the original samples were divided into upper and lower halves) were written by the same individual. For twins there were 1236 verification cases -- including 824 tests where the textual content of writing was different, and 412 tests where it was the same. An additional set of 1648 test cases were obtained from handwriting samples of nontwins (general population). To make the handwriting comparison, the system computed macro features (overall pictorial attributes), micro features (characteristics of individual letters), and style features (characteristics of whole-word shapes and letter pairs). Four testing scenarios were evaluated: twins and nontwins writing the same text and writing different texts. Results of the verification tests show that the handwriting of twins is less discriminable than that of nontwins: an overall error rate of 12.91% for twins and 3.7% for nontwins. Error rates with identical twins were higher than with fraternal twins. Error rates in all cases can be arbitrarily reduced by rejecting (not making a decision on) borderline cases. A level of confidence in the results obtained is given by the fact that system error rates are comparable to that of humans (lower than that of lay persons and higher than that of questioned document examiners [QDEs]).     

Distinguishing Characteristics of Robotic Writing

Advances in robotic handwriting technology create new challenges for forensic document examiners. In the past, devices such as the autopen were used to replicate signatures of government officials and corporate companies. In today's technology, companies such as Bond utilize robots to create written documents, which mimic natural patterns of handwriting. They generate customizable written samples by simulating pen movements and letter formations. Four forensic document examiners were given various reproduced questioned documents and utilized a modified ACE‐V (analysis, comparison, evaluation, verification) methodology to determine their genuineness. Examiners were able to make a distinction between the human writing samples and the skilled robotic equivalents. Several distinct features that are not seen in natural handwriting, such as even pen pressure and the superimposition of letterforms were observed in the robotic samples. Careful examination of identifying features of the Bond produced documents resulted in an opinion of nongenuineness.     

书写习惯未定型成年人笔迹检验

目的研究书写习惯未定型成年人笔迹的检验方法。方法通过实例研究分析成年人笔迹变化的特点和原因,确定笔迹性质和检验方法。结果书写习惯未定型也是成年人笔迹变化的重要原因。书写习惯未定型成年人笔迹是成年人正常笔迹的例外,适用正常笔迹检验方法。结论本研究确立了检材笔迹与样本笔迹非本质差异的判断标准,适用于短时间内变化较大的成年人笔迹的同一认定。     

Identification of the Class Characteristics in the Handwriting of Polish People Writing in English

Abstract: An investigation was carried out to identify the class characteristics of Polish people writing in English and to specifically identify those characteristics that separate Polish handwriting from English handwriting. In the first stage, 40 Polish and 40 English handwriting samples were collected and systematically examined. In total, 31 features were identified that occurred in ≥25% of the Polish handwriting samples and therefore considered class characteristics. Of these, chi‐square analyses identified 21 class characteristics that occurred significantly more in Polish compared to English handwriting. Twenty‐one of the class characteristics in the Polish handwriting had similar constructions to the copybook pattern thus supporting the theory that class characteristics frequently stem from the taught writing system. In the second stage, an algorithm was developed using seventeen of the class characteristics that successfully discriminated between a further 13 Polish and 12 English handwriting samples.     

中文笔迹性别差异的研究

目的考察中文笔迹的性别差异。方法采用中文笔迹测验材料对236名大学生的书写样本进行了测量,并对笔迹特征进行了统计分析。结果男性的书写水平低于女性,男性书写速度比女性快,男性笔迹较潦草,轻重疾徐的节奏感较弱;男性书写时所留页边比女性小;男性笔迹的连笔比女性多,转折角度比女性大;男性笔迹的字行间距大于女性。     

卧姿笔迹特征的实验研究

目的为卧姿笔迹鉴定提供识别和评断的参考依据。方法比较108个不同书写水平者的仰卧、左侧卧、右侧卧及俯卧笔迹与正常坐姿笔迹特征上的异同点,通过大量实验数据的统计分析,总结出卧姿笔迹特征及其变化规律,探讨可能的变化原因,并分析卧姿笔迹检验的要点。结果卧姿笔迹在字体、写法、错别字、笔顺、字间组合和单字的基本搭配比例等特征上较稳定。这些特征可作为本质特征使用。4种卧姿中,俯卧笔迹特征最稳定;书写水平高者笔迹特征也较稳定。结论卧姿笔迹鉴定应结合卧姿笔迹特征变化规律,准确判断笔迹的形成条件,去伪存真,做出科学的评断。     

Using subsampling to estimate the strength of handwriting evidence via score-based likelihood ratios

The likelihood ratio paradigm has been studied as a means for quantifying the strength of evidence for a variety of forensic evidence types. Although the concept of a likelihood ratio as a comparison of the plausibility of evidence under two propositions (or hypotheses) is straightforward, a number of issues arise when one considers how to go about estimating a likelihood ratio. In this paper, we illustrate one possible approach to estimating a likelihood ratio in comparative handwriting analysis. The novelty of our proposed approach relies on generating simulated writing samples from a collection of writing samples from a known source to form a database for estimating the distribution associated with the numerator of a likelihood ratio. We illustrate this approach using documents collected from 432 writers under controlled conditions.     

Development of Individuality in Children's Handwriting

Handwriting of children in early grades is studied from the viewpoint of quantitatively measuring the development of handwriting individuality. Handwriting samples of children, in grades 2–4, writing a paragraph of text in both handprinted and cursive, collected over a period of 3 years, were analyzed using two different approaches: (i) characteristics of the word “and” and (ii) entire paragraphs using an automated system. In the first approach, word characteristics were analyzed using statistical measures. In the second approach, pairs of paragraphs were compared. Both types of analysis, single word and complete writing, led to the same conclusions: (i) handwriting of each child remains relatively similar when handwriting has been just learnt and becomes markedly different from grades 3 to 4 and (ii) handwriting of different children becomes progressively more different from grades 2 to 4. The results provide strong support that handwriting becomes more individualistic with child development.     

A statistical approach to aid examiners in the forensic analysis of handwriting

We develop a statistical approach to model handwriting that accommodates all styles of writing (cursive, print, connected print). The goal is to compute a posterior probability of writership of a questioned document given a closed set of candidate writers. Such probabilistic statements can support examiner conclusions and enable a quantitative forensic evaluation of handwritten documents. Writing is treated as a sequence of disjoint graphical structures, which are extracted using an automated and open-source process. The graphs are grouped based on the similarity of their shapes through a K-means clustering template. A person's writing pattern can be characterized by the rate at which graphs are emitted to each cluster. The cluster memberships serve as data for a Bayesian hierarchical model with a mixture component. The rate of mixing between two parameters in the hierarchy indicates writing style.     

书写能力的结构

目的提出人的书写能力由基础因子构成的假说。方法根据因子说,不同字的笔顺可能相关。以反犬旁、山字为目标字,收集799份有效实验样本,分性别检验实验样本中2个目标字的笔顺是否相关。结果统计检验表明反犬旁笔顺与山字笔顺相关（p〈0.01）,用一个笔顺在另一个笔顺出现的条件下的出现率与它的出现率之比测定它们相关性的大小,最高的比值为3.65。结论证实了人的书写能力由基础因子构成的假说,这个假说可以作为笔迹比较的理论基础。     

浅议酒后笔迹特征与检验要点

随着时代经济的飞速发展,商业贸易往来日趋频繁,人们越来越热衷于在酒桌上谈论商业及个人事宜,并在酒至半酣后签订合同,协议,借据,收据等文书。但往往在酒醒的那一刻,把醉酒后签字的事情遗忘或部分遗忘,造成纠纷。于是,对于酒后笔迹特征的检验也显得日益重要。通过对一些酒后笔迹的研究,对此类笔迹特征的变化与检验要点进行了粗浅的分析。     

论笔迹学中的“运笔”

文字的书写过程,其实质是用笔写字的动作完成过程,故笔迹必然反映运笔动作。研究笔迹必然分析运笔,不仅应重视运笔动作本身,还应重视动作实现过程中的相关制约因素,从而力求从运笔的内涵和形成要件、笔迹对运笔动作及其相关制约因素的反映方式和程度两个方面进行系统、深入的分析,以此揭示笔迹鉴定的根本属性,即借助对笔迹表象的比对分析,从本质上认定书写习惯体系的同一性。然后探索笔迹鉴定过程中特征认识和判断的依据与标准,力求在笔迹学理论中形成对运笔的系统认识和总结。     

生理因素和环境因素对双生子笔迹影响的研究

目的 研究双生子由于受共同生理因素影响,教育和环境影响对笔迹特征影响的差异.方法 收集了80对双生子的笔迹,采用统计分析的方法进行研究.结果 书写水平、字的大小、字形、字行间距、书写速度特征受生理因素的影响较大,环境因素对竖长、撇长、转折角度、页边、错别字、笔画变异、笔画形态、搭配比例、写法、笔顺特征的影响更大.结论 生理因素和环境因素对笔迹的影响并不是彼此完全独立的,二者往往通过复杂的方式交互作用影响笔迹,一级亲属笔迹鉴定中应注意的选择特殊性强的笔迹特征全面比较.     

Use of an Automated System to Evaluate Feature Dissimilarities in Handwriting Under a Two-Stage Evaluative Process*†

The two-stage evaluative process is an established framework utilized by forensic document examiners (FDEs) for reaching a conclusion about the source(s) of handwritten evidence. In the second, or discrimination, stage, the examiner attempts to estimate the rarity of observations in a relevant background population. Unfortunately, control samples from a relevant background population are often unavailable, leaving the FDE to reach this determination based on subjective experience. Automated handwriting feature recognition systems are capable of performing both feature comparison and discrimination, yet these systems have not been subjected to empirical validation studies. In the present study, we repurposed a commercially available automated system to generate empirical distributions for ranking feature dissimilarity scores among pairs of handwritten phrases. The blinded results of this automated process were used to survey an international cohort of 36 FDEs regarding their strength of support for same- and different-writer propositions. The survey served to cross-validate FDE decision-making under the two-stage approach. Results from the survey demonstrated a clear pattern of response consistent with ground truth. Predictive regression analyses indicated that the automated feature dissimilarity scores and the log of their cumulative distribution functions accounted for 72% of the variability in FDE opinions. This study demonstrated that feature dissimilarity scores acquired using automated processes and their distributions are closely aligned with FDE decision-making processes supporting the heuristic value of the two-stage evaluative framework.     

Significance of sequence of strokes in Chinese handwriting examination

This paper reports a statistical study on the sequence of strokes of 61 commonly encountered Chinese radicals and characters written by 372 invited subjects. The distribution of different writing sequence of these Chinese radicals and characters was examined. Comparison of the sequence of strokes executed by the subjects with the standard rule of writing these Chinese radicals and characters revealed that around 60% of the subjects wrote in the correct sequence. Pair comparison of sequences of strokes in Chinese handwriting among the 372 subjects was also performed. The results demonstrated that no two individuals wrote all the 61 radicals and characters with the same sequence of strokes. The findings indicate that, despite some basic rules governing the writing sequence of Chinese characters, writers tend to develop their own habits. The findings also support the hypothesis that the handwriting of experienced writers is individual.     

浅谈笔迹线条主动触觉在笔迹鉴定中的运用

笔迹是书写运动的轨迹,在观察静态特征的同时运用其动态特征,无疑可以提高笔迹鉴定的水平。但如何获取字迹的书写压力、书写速度和加速度等动态特征,目前还是个难题。笔迹心理学中笔迹线条主动触觉的分析是将笔迹书写时的压力与速度贯穿于字迹观察分析的始终,将其运用于笔迹鉴定,可在传统的笔迹鉴定二维平面字迹特征的视觉观察分析模式基础上,将视觉观察与触觉体验相结合,形成字迹形态二维平面特征与书写时笔向下的力度,和沿笔画书写的速度相结合的四维特征观察分析模式。     

笔迹样本及提取技巧

在笔迹检验中,笔迹样本是否可靠、充分、具有可比性,直接关系到鉴定结论准确与否。如果提取的样本不符合鉴定要求,即使找准了嫌疑对象,也难以做出同一认定结论。如何提取符合鉴定要求的笔迹样本,作者参考有关文献,结合二十年来在基层从事笔迹检验实践的体会,研究探讨了笔迹样本的种类、条件及提取技巧。以期为文检同行及公检法办案人员抛砖引玉。     

写字机器人伪造签名字迹的鉴别

目的通过实验研究使用写字机器人伪造的签名字迹特征,减小文件检验鉴定中的错判风险。方法以真实书写字迹为模板、使用市面上主流款式的写字机器人执不同种类书写笔进行书写,通过直接观察、显微观察、反射变换成像(RTI)方法观察等方式比对手写字迹和机器人书写字迹的差异,归纳写字机器人伪造字迹的主要特征,总结出有效的检验鉴别方法。结果通过研究发现写字机器人伪造签名笔迹的特点主要有起收笔为顿压笔,笔画出现细微的抖动歪曲现象,整体笔画笔压均匀,运笔生硬无笔势等。结论目前写字机器人伪造签名字迹与真实手写字迹还有一定差异,使用反射变换成像(RTI)方法观察能达到较好的检验效果。     

汉字文字布局特征新探——从书写动作系统方面进行研究

文字布局特征是脱离了规范文字布局动作特点的反映,因而对文字布局特征的研究必须以书写动作系统及其特性为基础。文字布局动作系统具有相对的独立性和自身的特殊性、稳定性,并反映出相应的笔迹一般特征和细节特征。所以,通过研究书写动作系统来探索文字布局特征的科学基础及其特征价值,对完善笔迹鉴定科学基础理论和笔迹特征体系具有一定的价值。     

笔迹动态特征研究

笔迹是通过书写运动形成的轨迹,由静态要素和动态要素所组成,承载着时间和空间信息。笔迹动态特征是客观存在的,它是书写人书写技能和书写习惯的外在表现,主要包括速度特征、笔力特征、脉冲特征、节奏特征等。对笔迹动态特征进行研究,多视域地挖掘和认识笔迹特征,可为笔迹检验鉴定意见提供更全面、更深层的支撑。