引用本文
蒋焕, 陈立宏, 李俐明, 张嘉兴, 刘发福, 熊向阳. 不同年龄阶段人的硅胶仿生指纹印泥痕迹特征[J].刑事技术, 2022,47(4):400-404
JIANG Huan, CHEN Lihong, LI Liming, ZHANG Jiaxing, LIU Fafu, XIONG Xiangyang. Characteristics of Silicone Bionic Film-fingerprints from Age-specified Different People Tested with Their Inkpad-revealed Deliveries[J]. Forensic Science and Technology,2022,47(4): 400-404  
Doi: 10.16467/j.1008-3650.2022.0016
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Copyright©2022, 《刑事技术》编辑部
《刑事技术》编辑部
不同年龄阶段人的硅胶仿生指纹印泥痕迹特征
蒋焕1, 陈立宏2, 李俐明3, 张嘉兴4, 刘发福5, 熊向阳6
1.吉林警察学院,长春 130117
2.中国刑事警察学院,沈阳 110854
3.长春市公安局朝阳分局,长春 130012
4.长春市公安局经开分局,长春 130022
5.喀什地区公安局,新疆 喀什844000
6.辽源市公安局,吉林 辽源 136200

第一作者简介：蒋焕,女,山东泰安人,硕士,副教授,研究方向为痕迹检验。E-mail: 623039849@qq.com

收稿日期: 2021-11-19 修回日期: 2022-03-28
摘要

研究不同年龄阶段人的硅胶仿生指纹膜印泥痕迹特征与真实指纹印泥痕迹特征的差异,为识别硅胶仿生指纹印泥痕迹提供依据。分别制作青年、中年、老年三个年龄段各100名人员的硅胶仿生指纹膜,然后用硅胶仿生指纹膜和同一手指在相同情况下蘸取印泥,分别以轻、中、重 3 种力度在 A4 纸上垂直按压形成印泥指印,比较硅胶仿生指纹膜印泥痕迹与真实指纹印泥痕迹的特征差异。结果表明不同年龄阶段人的硅胶仿生指纹膜印泥痕迹在空白特征、断裂特征等方面差异明显,青年组硅胶指纹膜相对质量高,得到的指印效果也好,随着年龄增长,纹线断裂等特征呈增多趋势,至老年阶段纹线断裂痕迹明显,印痕模糊不清,瑕疵也较多,与真实指纹痕迹的区别最明显。两者之间的特征差异可以帮助识别硅胶仿生指纹印泥痕迹。

关键词: 指纹; 硅胶仿生指纹膜; 印泥痕迹; 特征差异; 年龄
中图分类号:DF794.1 文献标志码:A 文章编号:1008-3650(2022)04-0400-05
Characteristics of Silicone Bionic Film-fingerprints from Age-specified Different People Tested with Their Inkpad-revealed Deliveries
JIANG Huan1, CHEN Lihong2, LI Liming3, ZHANG Jiaxing4, LIU Fafu5, XIONG Xiangyang6
1. Jilin Police College, Changchun 130117, China
2. Criminal Investigation Police University of China, Shenyang 110854, China
3. Chaoyang Branch of Changchun Public Security Bureau, Changchun 130012, China
4. Jingkai Branch of Changchun Public Security Bureau, Changchun 130022, China
5. Kashi Public Security Bureau, Kashi 844000, Xinjiang, China
6. Liaoyuan Public Security Bureau, Liaoyuan 136200, Jilin, China
Abstract

Silicone bionic film-fingerprint, also called “clone fingerprint”, is a film made of silicone that coalesces with a gel on which one person’s fingerprint had been previously impressed and solidified. At present, there are studies about mark characteristics of silicone bionic film-fingerprint on different objects home and abroad, yet rarity for people of different ages. In addition, the manufacturing technology of silicone bionic film-fingerprint is of constant improvement, resulting in the relevant mark characteristics of fingerprint being changed accordingly. Hence, the studies were here carried out about the mark characteristics into their difference between the inkpad-revealed silicone bionic film-fingerprint and its real fingerprint counterpart from people of different ages. The silicone bionic film-fingerprints were made for 100 people of each from three age groups: young (18-45 years old), middle-aged (46-69 years old) and old (>69 years old), thus having the silicone bionic film-fingerprint and its same real finger impressed into inkpad under the identical conditions and then pressed vertically onto A4 paper with light, medium and heavy forces. Therefore, such the inkpad-revealed fingerprints were formed and photographed, leaving themselves into the comparison of characteristic difference against their real fingerprint counterparts. The results showed that the marks of silicone bionic film-fingerprint from age-different people are significantly discrepant in the “blank” and “fractured” features. Apparently, the young people seems to deliver the relatively high quality of silicone bionic film-fingerprint and good effect of inkpad-revealed fingerprinting. The age increasing brings forth the features, e.g., the broken ridges, tending to augment until the old-aged people are revealing more obvious broken ridge marks, blurred fingermarks and flaws with their inkpad-revealed silicone bionic film-fingerprints demonstrating most distinct difference of feature against the real fingerprint counterparts among the three groups. The inkpad-revealed silicone bionic film-fingerprints and related marks can get to identify with their characteristic differences from those of the real ones.

Key words: fingerprint; silicone bionic film-fingerprint; inkpad-revealed mark; characteristic difference; age

指纹识别技术以其自身的独特属性立足于生物识别技术行列之中, 但伪造者正是利用指纹与人身识别二者间的关联性达到其违法犯罪的目的[1]。日本国立信息学研究所日前在试验中发现, 距离3 m拍摄的V字手势照片发到网上或被盗取指纹[2]。同时, 网上流传有很多简单易懂的指纹膜制作视频, 犯罪分子只需要看几分钟视频, 便能掌握硅胶仿生指纹膜的制作技术, 这无论是对于信息安全还是财产、生命安全都是一个巨大威胁。因此如何识别伪造指纹也就成了侦查部门和鉴定人员在新时期遇到的新难题, 也是刑事科学技术发展过程中所面临的重大课题。目前国内外学者对不同客体上硅胶仿生指纹膜印痕特征进行了研究[3], 但未见对于不同年龄阶段人的硅胶仿生指纹膜痕迹特征研究, 同时, 硅胶仿生指纹膜的制作技术也在不断改进, 其痕迹特征也相应地有了新的变化, 因此硅胶仿生指纹痕迹特征还需要进行更系统的研究, 这不仅是实务界需要直视的重点问题, 也是理论界为完善指纹理论体系所必须研究的一个方面[1]。

本文比较分析青年、中年、老年三个年龄段人的硅胶仿生指纹膜印泥痕迹和真实指纹印泥痕迹的特征差异, 由此总结得到不同年龄段人的硅胶仿生指纹膜印泥痕迹特征。

1 材料与方法
1.1 实验材料

纳米材料模型胶（亿城制品厂）, 液态硅胶、硅胶固化剂（巨密实业有限公司）; 采集盘、搅拌盒、注射器、打火机、A4 纸、印泥、电子天平、Nikon D800照相机、徕卡EZ4D体视显微镜、酒精灯、酒精等。

1.2 实验方法

1.2.1 硅胶仿生指纹膜的制作

1）用酒精灯侧焰加热软化纳米模型胶, 均匀加热30 s;

2）待纳米模型胶冷却10 s后, 开始采集指纹。手指垂直按压模型胶, 静止60 s;

3）用针管吸取约1 mL液态硅胶注入搅拌盒内, 滴入三滴固化剂, 搅拌20 s;

4）将搅拌均匀的混合液注入已经按压完毕的模 型胶内, 静置3 h, 等待液态硅胶固化;

5）用镊子小心取出已经凝固的硅胶指纹膜。

1.2.2 印泥痕迹样本的制作

1）选择青年（18~45岁）、中年（46~69岁）、老年（> 69岁）三个年龄段的各100名人员为指纹样本提供者, 每个年龄阶段男性、女性各50名, 使用1.2.1方法制作每名人员的硅胶仿生指纹膜共300枚。

2）在硅胶仿生指纹膜表面均匀涂抹印泥, 将A4纸放在电子秤上, 每枚指纹膜均分别以轻度（80~120 g）、中度（260~300 g）、重度（460~500 g）的垂直力按压A4纸, 形成硅胶仿生指纹膜印泥痕迹样本, 每种力度各300枚。

3）将同一手指蘸取印泥后, 按照上述方法分别制作轻度、中度、重度真实指纹印泥痕迹样本各300枚。

4）使用照相机对以上痕迹拍照。

2 结果与讨论

所有样本比对发现, 硅胶仿生指纹膜印泥痕迹整体纹线流畅、较自然, 特征表现较好, 但其纹线稍变粗、纹线间隔稍变小, 也容易形成“ 起点” “ 终点” 等假细节特征, “ 分歧” “ 结合” 等部分细节特征不明显, 而真实指纹印泥痕迹纹线连贯、清晰。硅胶仿生指纹膜印泥痕迹会出现数量不等的空白区域, 空白区域形状多不规则, 数量和面积随着按压力度的增大而明显减小, 同时随着年龄的增加, 肌肉松弛, 弹性减弱, 表面角质化严重, 粗糙不平, 因此印痕质量也有所下降, 青年和中年阶段人的硅胶仿生指纹膜与真实手指印泥手印的相似度较高, 若鉴定人没有识别伪造指印的意识和技术方法, 则容易出具错误的鉴定意见[4]。

2.1 断裂特征分析

由于印泥与硅胶仿生指纹膜之间的附着力大于印泥与纸张之间的附着力[3], 所以轻度压力下的硅胶仿生指纹膜印泥痕迹纹线不连续、“ 断裂” 现象明显, 随着按压力度的增加, 纹线连续性增强、“ 断裂” 痕迹减少。

随着年龄的增加皱纹增多, 至老年时期, 组织萎缩, 皮肤变薄, 皱纹明显, 真实手印中多为长条状或梭状的空白, 走向弯曲不固定呈闪电样式, 指纹膜印泥痕迹裂痕形状反映不全[3]。如图1所示。

图1 不同压力下不同年龄组真实指纹和硅胶仿生指纹膜印泥痕迹断裂特征（a：轻度压力下青年组; b：中度压力下中年组; c: 中度压力下老年组。左：真实指纹; 右：硅胶仿生指纹膜）Fig.1 Fracture characteristics of inkpad-revealed real fingerprints and their counterparts of silicone bionic film-fingerprint from age-different people under discrepant pressure (a: of young people under light pressure; b: of middle-aged people under medium pressure; c: of old people under medium pressure) (left: of real fingerprint; right: of silicone bionic film-fingerprint)

2.2 边缘特征分析

真实指纹印泥痕迹边缘纹线排列整齐且完整, 呈圆弧形, 印泥分布均匀, 颜色过渡自然。硅胶仿生指纹膜印泥痕迹会出现边缘纹线不整齐, 并有不同程度的挤墨现象, 如图2箭头所示, 甚至有的周围纹线呈棱角形态突然缺失, 印泥分布不均匀, 颜色过渡不自然; 有时还会出现边角特征, 如图3所示, 边角特征出现的主要原因是捺印时硅胶仿生指纹及其平面部分在同一作用力下同时被转移到纸张上, 以及在制作硅胶仿生指纹膜时, 因操作不当导致的指模表面及周围凹凸不平。这种边角特征具有随机性, 有时也不会出现[5-7]。

图2 轻度压力下中年组真实指纹和硅胶仿生指纹膜印泥痕迹边缘特征（左: 真实指纹印泥; 右: 硅胶仿生指纹膜）Fig.2 Edge characteristics of inkpad-revealed real fingerprints and their counterparts of silicone bionic film-fingerprint from the middle-aged people under light pressure (left: of real fingerprint; right: of silicone bionic film-fingerprint)

图3 中度压力下青年、中年组硅胶仿生指纹膜印泥痕迹边角特征（左：青年; 右：中年）Fig.3 Corner-place characteristic patterns appearing with the inkpad-revealed silicone bionic film-fingerprints of young and middle-aged people under medium pressure (left: of young people; right: of middle-aged people)

2.3 汗孔特征分析

青年阶段因为活动较多, 汗液分泌较多且分泌量大, 使纹线有光泽感, 汗孔呈较完整的圆孔状, 比较容易被观察到, 随着按压力度的增大, 小白点的面积也减小, 印泥颜色变深; 随着年龄的增长, 汗孔边缘逐渐粗糙变成多角缺损, 呈不规则形态, 汗孔特征逐渐模糊, 至老年阶段, 汗孔难以被观测到[8]。而在硅胶仿生指纹膜印泥痕迹中, 汗孔特征一般无法反映, 主要是由于汗孔形态细微, 硅胶仿生指纹膜单根纹线延伸扩张, 使得单根纹线变粗、间距变小, 填充了汗孔部位的漏白, 导致汗孔特征反映差[5], 如图4所示。

图4 轻度压力下青年组真实指纹印泥痕迹汗孔特征和硅胶仿生指纹膜印泥痕迹（左：真实指印; 右：硅胶仿生指纹膜印痕）Fig.4 Sweat-pore characteristics of inkpad-revealed real fingerprints and their counterparts of silicone bionic film-fingerprint from the young people under light pressure (left: of real fingerprint; right: of silicone bionic film-fingerprint)

2.4 墨迹分布特征分析

真实指纹单根纹线印泥痕迹存在墨迹轻重、深浅的变化及细微漏白等特点, 因为手指单根乳突纹线的表面不是平滑的, 乳突纹线脊顶有凹凸变化, 乳突纹线边缘有缺损或凸出, 捺印时手指乳突纹线凸起的部位对应的痕迹颜色深、墨迹重, 手指乳突纹线凹下的部位对应的痕迹颜色浅、墨迹轻, 或者细微漏白, 并且颜色深浅之间有过渡, 墨迹分布有立体感。硅胶仿生指纹膜墨迹平实、色调单一、无立体感, 因为硅胶仿生指纹膜纹线平整, 表面无凹凸变化, 且留印均匀, 因此其痕迹缺少墨迹轻重的变化及过渡[4]。图5为使用PS软件进行去色、反相处理后的图片。

图5 真实指纹印泥痕迹（左）和硅胶仿生指纹膜印泥痕迹（右）Fig.5 Marks of inkpad-revealed real fingerprint (left) and its counterpart inverted from silicone bionic film-fingerprint (right)

3 结论

硅胶仿生指纹膜印泥痕迹较真实指纹印泥痕迹纹线稍变粗、纹线间隔稍变小, 汗孔等细微特征没有反映; 边缘纹线不整齐, 甚至有的周围纹线呈棱角形态突然缺失, 印泥分布不均匀, 颜色过渡不自然; 单根纹线墨迹分布平实、色调单一、缺少轻重及深浅变化, 无立体感, 有时会出现边角特征等特点。不同年龄阶段人的硅胶仿生指纹膜印泥痕迹在空白特征、断裂特征等方面差异明显, 青年组硅胶指纹膜相对质量高, 得到的指印效果也好, 随着年龄增长, 纹线断裂等特征呈增多趋势, 至老年阶段纹线断裂痕迹明显, 印痕模糊不清, 瑕疵也较多, 与真实指纹痕迹的区别最明显[9]。

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