伪装样本笔迹的现场识别

介绍了鉴定人要从认识伪装笔迹的特点、详细了解案情入手,在做好嫌疑书写人的思想工作、反复让嫌疑书写人书写“有关”笔迹的基础上,在嫌疑书写人正在书写样本笔迹时现场识别伪装样本笔迹的方法。     

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。     

书写习惯多样性的同一认定研究

有的书写人书写习惯存在书写习惯多样性样式和书写习惯多样性局部表现两种形式,这对笔迹鉴定的科学基础、逻辑关系等科学性问题有重要的影响.对此就书写习惯多样性的构成及特点、内在的逻辑联系等问题进行探讨,在此基础上提出对存在书写习惯多样性的笔迹鉴定样本、特征差异的评断以及鉴定意见表述等的要求.这一方面有利于完善笔迹鉴定的基础理论,另一方面则有利于避免因对书写习惯多样性认识存在缺陷而导致的鉴定意见错误.     

浅谈笔迹样本的种类、条件及提取方法

笔迹样本是指由刑事案件的犯罪嫌疑人、被告人,民事、行政案件的当事人以及其他与案件有关联的人亲笔书写的,用来与检材笔迹物证上的字迹进行比较鉴别的字迹材料,是犯罪嫌疑人、当事人及关联人(以下均称嫌疑人)书写习惯特征的集中体现。因此,笔迹样本是否真实可靠、充分、具有可比性,直接关系到鉴定结论准确与否。侦查、调查中,即使找准了嫌疑对象,但收取的样本不符合鉴定条件,同样难以作出科学准确的鉴定结论。之所以出现这类情况,主要是因为侦查、检察、审判人员对笔迹样本应具备的条件认识不够,提取方法不当,以致一次送检样本就合格的很…     

民事案件中左手伪装笔迹的检验1例

左手伪装笔迹,一般是指书写人出于歪曲自身笔迹特征的目的,故意采取非利手(一般情况是为右利手书写的人采取左手书写的情况)进行书写的特殊伪装书写方式所形成的笔迹.作为非正常笔迹检验项目,鉴定人有必要严格地依据鉴定技术规范,灵活运用伪装笔迹鉴定的基本理论,结合逻辑经验,对检材字迹中的"假象"予以系统分析、甄别,同时还需要结合科学取样工作,确保检验工作质量.同时,在以往的笔迹检验工作中,左手伪装笔迹多出现在刑事案件里,作为犯罪嫌疑人逃避打击而采取的手段,而在民事案件中被涉诉当事人利用的情形则较为少见.本文通过民事案件中的左手伪装笔迹检验案例,提出检验左手伪装笔迹的几点体会,供同行商榷.     

不确定性笔迹鉴定结论研究

笔迹鉴定人员经常由于不能确定或排除可疑笔迹书写人而被视为逃避责任。实际上,基于以下客观原因,鉴定人员往往难以得出确定性的结论:首先,笔迹比较检验的特征包括开放集而非闭合集,在闭合集中存在相同点,我们只需要寻找特定的特征即可。而在开放集中,并不知晓是否存在相同点,因此需要更为严格的审查标准;其次,证据材料的数量和质量都可能达不到要求;最后,排除可疑笔迹书写人的过程往往不能得出确定性结论,在可疑笔迹和已知样本之间相同点的缺乏不能成为它们出自不同书写人的充足理由。     

论笔迹检验理论的基本范畴

笔迹作为一类检验客体和一门科学的研究对象,其现象的丰富具体和本质的抽象概括决定了笔迹检验理论的基本范畴是由点、线、面的平面视觉表象与系统抽象的多维整体、相对稳定的静态结构与绝对运动的动态模式、书写目的单一与书写手段的多样以及笔迹真象与笔迹假象的有机结合和辩证统一.研究笔迹检验理论的基本范畴,对于丰富笔迹检验理论和检验技术有着重要意义.     

左手伪装笔迹的特征鉴别与同一认定

目的通过对于左手伪装书写方式的判断与反映书写人本质习惯特征的鉴别,为左手伪装笔迹的识别与书写人同一认定提供客观依据。方法在提取右利者左、右手分别所书写笔迹的基础上,对其左手伪装书写的字迹与其右手正常字迹进行比较、分析与检验。结果人类大脑所特有的生理属性以及书写技能互相迁移的特点,令左手伪装笔迹在包含左手字典型特点与易变特征的同时,亦反映了诸多书写人自身书写习惯的笔迹特征。结论左手伪装笔迹特征的鉴别,不仅可以确认左手书写这一伪装方式,更可进一步对前述特殊笔迹的书写人予以同一认定。     

笔迹检验中案后笔迹样本的收集和利用

在笔迹检验中，只要能收集到书写人的案前笔迹样本，一般均能完成检验的要求，但在有些案件中，收集案前笔迹样本比较困难，就需要利用案后笔迹样本进行检验。案后笔迹样本的收集通常采用让其所在单位组织统一的考试、开展问卷调查、撰写情况汇报和学习体会等形式进行，有时这些方法不一定奏效。笔者在工作实践中总结出两种案后笔迹样本的收集方法，介绍如下。     

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。     

Investigating forensic document examiners’ skill relating to opinions on photocopied signatures

Many forensic document examiners are hesitant to express authorship opinions on photocopied handwriting as the photocopying process results in less feature information than original writing. This study aimed to test the accuracy of 15 examiners' opinions regarding whether photocopied questioned signatures were genuine or simulated. Each examiner received the same set of original signature exemplars, from one individual, and a set of eighty questioned photocopied signatures comprising of genuine and simulated signatures. The overall misleading (error) rate for the grouped examiners' opinions was 0.9% providing strong evidence that examiners can make accurate observations regarding the authorship of non-original handwriting.     

Are expert penmen better than lay people at producing simulations of a model signature?

Although forensic signature examination is considered to be an identification science, it is a theoretical possibility that an individual may learn to forge another person's signature that is free from indications of simulation behaviours. This proposition was tested in a signature blind trial that was administered to 42 forensic handwriting examiners (FHEs). Participants expressed opinions on the authorship of 100 questioned signatures. The questioned signatures comprised a mixture of genuine, disguised and simulated signatures. Calligraphers formed part of the population of individuals who provided simulated signatures for the trial. A total of 3100 opinions were expressed of which 1254 were correct, 224 misleading and 1622 were inconclusive. Of the opinions expressed regarding the simulated signatures, the misleading score for the calligraphers' forgeries were approximately four times that of the lay persons' forgeries. These results provide strong evidence in support of the proposition that calligraphers are more skilled at simulating signatures than are lay people and can produce forgeries that some FHEs have difficulty detecting.     

Forensic Document Examiners’ Skill in Distinguishing Between Natural and Disguised Handwriting Behaviors

Abstract: Disguised handwriting is problematic for forensic document examiners (FDEs) and attracts higher misleading and inconclusive rates on authorship opinions than does genuine writing (Found B, Rogers D, International Graphonomics Society, 2005). There are currently no published empirical data on FDEs’ expertise in distinguishing between natural and disguised writing behavior. This paper reports on the skill of FDEs for determining the writing process of 140 pairs of natural and disguised writings and compares their results with those of a control group of laypeople. A significant difference was found between the examiner and lay group. FDEs’ expertise is characterized by their conservatism, where FDEs express a higher proportion of inconclusive opinions (23.1% for FDEs compared to 8.4% for the control group). This leads to the FDEs expressing a smaller percentage of misleading responses when calling writings as either naturally written or disguised (4.3% for FDEs compared with 12.2% for the control group).     

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。     

汉英文字笔迹特征的比较研究

目的更深入的了解不同国家、地区,不同文种,不同文化背景下的笔迹鉴定工作者对特定文字笔迹鉴定认识的差别。方法以中英文为例,对汉字和英文的特点和笔迹特征进行比较研究。结论汉英文字的笔迹特征分类体系大体相似,并无质的差别,但是不同文字的特点决定了其笔迹特征取向与侧重、价值评断、个别特征的使用率,以及对同一人笔迹特征多样变化的认识上还是有所区别,各具特色。     

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。     

Individuality of handwriting

Motivated by several rulings in United States courts concerning expert testimony in general, and handwriting testimony in particular, we undertook a study to objectively validate the hypothesis that handwriting is individual. Handwriting samples of 1,500 individuals, representative of the U.S. population with respect to gender, age, ethnic groups, etc., were obtained. Analyzing differences in handwriting was done by using computer algorithms for extracting features from scanned images of handwriting. Attributes characteristic of the handwriting were obtained, e.g., line separation, slant, character shapes, etc. These attributes, which are a subset of attributes used by forensic document examiners (FDEs), were used to quantitatively establish individuality by using machine learning approaches. Using global attributes of handwriting and very few characters in the writing, the ability to determine the writer with a high degree of confidence was established. The work is a step towards providing scientific support for admitting handwriting evidence in court. The mathematical approach and the resulting software also have the promise of aiding the FDE.     

Preparation of Disappearing Inks and Studying the Fading Time on Different Paper Surfaces

Abstract: Disappearing inks have been used in different fields, but it may be abused in forgery and counterfeiting. This research was conducted on the preparation of disappearing inks using different concentrations of thymolphthalein, phenolphthalein, and their mixture. The prepared inks were applied to different types of handwriting papers. It was found that the handwriting stability increased by increasing thymolphthalein, phenolphthalein, or alkali concentration, but in the case of using 4 mL of 1 normal (N) NaOH, the handwriting stability of phenolphthalein and its mixture inks decreased. Deciphering of the faded handwriting was evaluated by different methods; using optical deciphering, the faded handwriting did not respond to the different light sources. All the faded handwriting was visible when treated with alkaline solution. There was no change in the faded handwriting when heated to 100°C; phenolphthalein and mixture inks containing 0.5 mL of 1 N NaOH became red when only Azhar and Xerox papers were heated to 150°C.     

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]).