Visual attention and expertise for forensic signature analysis

Eye tracking was used to measure visual attention of nine forensic document examiners (FDEs) and 12 control subjects on a blind signature comparison trial. Subjects evaluated 32 questioned signatures (16 genuine, eight disguised, and eight forged) which were compared, on screen, with four known signatures of the specimen provider while their eye movements, response times, and opinions were recorded. FDEs' opinions were significantly more accurate than controls, providing further evidence of FDE expertise. Both control and FDE subjects looked at signature features in a very similar way and the difference in the accuracy of their opinions can be accounted for by different cognitive processing of the visual information that they extract from the images. In a separate experiment the FDEs re-examined a reordered set of the same 32 questioned signatures. In this phase each signature was presented for only 100 msec to test if eye movements are relevant in forming opinions; performance significantly dropped, but not to chance levels indicating that the examination process comprises a combination of both global and local feature extraction strategies.     

专业性练习摹仿签名笔迹鉴定的实验研究

目的本文通过实验对具有一定笔迹鉴定专门知识与不具备笔迹鉴定专门知识的人的练习摹仿签名笔迹进行实验分析研究。方法对两类人在练习的不同阶段形成的练习摹仿签名笔迹特征的一般状态表现,以及对其笔迹特征的形成、变化原因、鉴定价值分别进行了论述,并总结出其变化规律。结果为不同种类的练习摹仿签名笔迹的鉴定提供一定的识别和特征分析、评断的参考依据。     

Forensic medical expertise on burned bone remains

The series of 1138 cadaveric humerus and femurs of people of both sexes who died at the age of 17-91 years and 468 animal bones (cow, pig, sheep) was studied. Bones were burned (experimentally) at various temperature values and in different conditions. Investigations were carried out using osteometric, microscopic, microroentgenographic and mathematical methods. Species identification as well as sex and age determination using burned bone remains are possible regardless of the level of their burning. Regression equations to calculate victim's stature according to fragments of burned bones were received.     

Forensic psychophysiological expertise with application of polygraph

The notions of psychophysiological investigation (PPI) and psychophysiological examination with application of polygraph are characterized. The history of the method for more than 100 years, the aims of the examination are described. Effective use of the polygraph in criminal investigations is illustrated. The absence of methodological regulations and difficulties in training specialists hinder wide introduction of polygraphs into practice. How to get over these difficulties is shown.     

Forensic examination of effects of Parkinsonism on various handwriting characteristics

Parkinsonism is a neurodegenerative syndrome that causes impairment of motor skills in affected persons. Thus, adverse effects may be produced in the handwriting of persons suffering from Parkinsonism. Medication used for the treatment of Parkinsonism is known to subside certain motor defects for specific time intervals, showing slight differences or improvement in certain handwriting characteristics during those intervals on the same day as compared to the ones executed before medication. Certain handwriting characteristics affected due to Parkinsonism may be mistaken as forged features due to poor line quality, which can cause suspicion upon the authenticity of important legal documents. The present research work has been carried out to determine the effects of Parkinsonism and medication used for its treatment on handwriting. Handwriting/signature samples executed before and after the onset of Parkinsonism (both pre- and post-medication) have been randomly collected from 70 participants. These handwritings have been evaluated separately and compared inter-se for various handwriting characteristics with qualitative and statistical approach. The results have demonstrated significant changes in most of the characteristics in both affected writings of majority of participants as compared to their corresponding earlier writings. Thus, forensic document experts should be aware of the detrimental effects of Parkinsonism on handwriting in pre- and post-medication conditions of this ailment.     

Color separation of signature and stamp inks to facilitate handwriting examination

The questioned documents laboratory often encounters cases where handwriting that is to be examined intersects with some interfering factor such as a rubber stamp, typewriting or background printing. In these cases, line direction, beginning and ending features of letters and other fine details of the handwriting may be lost in the "noise" of the intersecting ink. The purpose of this paper is to show several new digital photography methods that may be used to "subtract" the effect of the intersecting ink, thereby enhancing that of the handwriting ink in order to enable the document examiner to conduct a complete examination. These methods have the advantage of being fast and do not involve the use of expensive material or equipment. Several new methods are described that may be used to separate the colors of the handwriting ink from that of the intersecting ink: the analog method and several digital methods such as RGB-HSB-CMYK, L*a*b color, and color separation using the Channel Mixer function of Adobe Photoshop. Successful application of these color separation methods to specific handwriting ink/rubber stamp ink color combinations shows that the effect of the intersecting ink may indeed be minimalized if not canceled altogether. Application of the suggested methods may well make the difference between a nonconclusive handwriting examination and a full analysis of the questioned handwriting.     

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。     

Eliminating ill-founded eliminations in handwriting comparison cases.

Document examiners sometimes eliminate writers on the basis of differences which are given too much weight. This article is an attempt to explain some conditions whereby differences in the writing of one individual are misinterpreted as significant differences, when they are actually caused by conditions which are unknown to the examiner.     

签名笔迹案例宏、中、微各层次特征数量规律统计研究

本文旨在从宏观、中观、微观三个层次统计研究签名笔迹特征的数量规律,客观认识在签名笔迹检验鉴定中各层次特征的应用.收集30份案例的鉴定书,统计签名笔迹各层次各特征的使用情况,认识特征的内在价值规律及在检验鉴定中的具体作用.经统计发现在检验鉴定过程中,微观层次特征使用率高、中观层次特征使用率较低,宏观特征使用率最低.持认定与持否定鉴定意见的案例有不同的侧重特征,本统计研究为签名笔迹量化提供数据基础.