对足迹检验鉴定理论的思考

我国的足迹检验技术在80年代和90年代得到了较大的发展,足迹检验技术从步法检验、形象检验,发展到鞋底磨损检验、足迹动力形态检验、足迹定量化检验等。特别是近几年,足迹检验中各学派、各门类的各种检验技术内容丰富,方法多样,正在逐步形成具有中国特色的足迹学体系,在侦查破案中发挥了重要作用。目前,常用的足迹鉴定包括:1赤足足迹的鉴定主要以足迹的大小、形象、轮廓、重压部位的密度、乳突花纹、残缺部位、是否变形等特征为赤足足迹进行同一认定,赤足足迹的鉴定又分为平面赤足足迹的鉴定和立体赤足足迹的鉴定。2鞋印足迹的形象鉴定主要…     

赤足跖后缘自动提取与自适应变模型特征识别

将经典Snake模型与自适应变模型相结合的算法，快速提取图像中的开边缘并识别边缘形状，实现赤足足迹跖后缘的自动提取与形状识别。首先，对原图像校正、平滑去噪，由数学形态学方法得到Snake模型的初始轮廓，迭代求解实现跖后缘的快速、精确提取。然后，由高次多项式进行数字滤波，再对滤波后的边缘曲线，利用先验知识，依据平均曲率的变化，自适应地选取不同的函数模型，提取出相应特征，自动识别边缘形状。该方法边缘提取准确，特征提取合理，使计算机总体识别率达到90％。     

利用不同鞋种鞋印长度推断身高差值探究

目的研究不同鞋种的鞋印长度与赤足平面足迹长度的差值数据,为利用现场各类不同穿鞋足迹分析身高等人身特点提供科学依据,也为足迹定量化分析与检验奠定基础。方法针对犯罪现场中常见鞋种,选取不同的鞋号,采集对不同足长、身高的实验者正常行走所捺印的穿鞋样本与赤足样本,对穿鞋足迹鞋印长度与赤足足迹长度进行统计与计算。结果得出不同鞋种鞋印长度与赤足平面足迹长度的差值数据。结论应用现场穿鞋足迹分析身高等人身特点时,应针对不同的鞋种,减去相关系数,结合原有身高分析公式,综合分析身高。     

利用残缺赤足足迹推算身高

目的由于主客观条件的影响,犯罪现场中常见的足迹多为不完整的残缺足迹,如何能够有效地利用残缺足迹,对案件破获往往具有至关重要的作用。方法从残缺赤足足迹的反映形态出发,选择足迹中明显、稳定的特征点,确定特征量,通过数理统计分析,建立残缺赤足足迹推算身高的经验公式。结果在4个特征量中,跖前缘突点到跟后缘突点的距离与身高的相关性最好,跖内、外缘突点到跟后缘突点的距离与身高具有一定的相关性。结论根据现场残缺赤足足迹的反映情况,也可以近似推断嫌疑人的身高特点,为侦查提供方向。     

利用立体赤足迹后跟后缘裂纹特征破获一起重大盗窃案

1983年,我区某县发生一起重大盗窃案,现场勘查中仅提取到一枚残缺不全的立体赤足迹。经检验,足迹为后跟部分,反映出的后跟大小、形态、落脚点、重压面的形态位置等特征均与嫌疑人赤足足迹样本后跟部位反映的特征相同,但缺少特定、稳定的特征,后我们利用两者后跟后缘所反映出的裂纹痕迹形态和位置的关系,认定了作案分子,破获了此案。     

基于深度度量学习的足迹图像检索算法

针对赤足迹光学图像相似度高，传统算法无法快速提取样本有效信息的问题，提出了一种基于深度度量学习的赤足迹图像检索算法，该算法使用多尺度特征融合结构构建主干网络并辅以批去除结构监督学习，同时在嵌入空间内构建动态难样本三元组，解决传统难样本三元组挖掘方式不合理的问题。构建了一个包含250人、2 500枚的赤足迹光学图像数据集，该算法在所构建的数据集上平均检索精度达到88.86%，高于传统难样本三元组算法，可有效地应用于赤足迹光学图像检索。该算法对于足迹领域的自动化识别具有积极意义。     

从足底压力分布看步法特征的可靠性

利用比利时FootScan压力传感器,对154名年龄在18至55岁之间的健康男性赤足正常行走时的足底压力数据进行提取,以运动生理学、运动生物力学及足迹步法特征理论为基础,用数理统计学方法对足迹压力数据进行了计算分析,对步法特征形成不同时期足与承受客体相互间的作用过程和作用方式进行深入、系统、定量的研究,进而对步法特征的传统理论进行验证,阐明了对步法特征理论中未经过科学验证部分的认识,并对步法特征理论中各类特征的可靠性及特征价值进行了初步的探讨,为今后的足迹步法特征检验鉴定工作和步法特征的发展完善都提供了有力的依据。     

足的解剖结构与足迹形成关系的研究

足迹是指存人体运动中,以赤足或穿鞋的足作为造痕体．与地面等承痕客体表面接触所形成的痕迹的总称。本文研究的足迹就是人体力学通过双脚造型的结果。     

粉末提取足迹

在现场勘查中,有些木质地板油面、地板革面、油漆涮过的水泥地面等,由于犯罪分子鞋底(或赤足)附着物少,在其地面上不易留下明显足迹。虽发现足迹,采用静电复印,直接或打侧光拍照、透明胶带直接粘贴等常见方法不易提取或效果不好。经过实践,采用毛刷蘸铝粉或青铜粉在地面上直接显现,效果较好,简单易行。具体方法是:勘查现场中,在木质地板油面,地板革面,油漆测过的水泥地面等客体上,虽没有发现明显足迹,但经过侧面打光照射和侧面观察,会发现加层或减层足迹轮廓。可用毛刷蘸铝粉或青铜粉在其客体上象显现指纹那样均匀的显现,有的可显现出足迹。然后再进行拍照,或用透明胶带直接提取,再粘贴在与其有反差的     

痕迹与气味提取并用1例

1 案情1997年7月15日傍晚,张某被人杀死后移尸于一水沟内,次日震被发现,因下雨现场已遭严重破坏.经勘查:在离尸体8cm处的棉花田里发现二枚可疑残缺足迹(显示赤足轮郭),尸体上掩盖着从山坡上折断的8根树枝,勘查中将这2枚足迹土和掩尸树枝上的痕迹气味及时提取,分别装于干净的磨口瓶内封存.2 提取方法(1)雨后足迹带土(加湿)提取法:由于此案的2枚足迹遗留在雨后棉花田的沙土地上(无水坑状),笔者先将纱布覆盖在足迹上轻轻摩擦感染2min～5min,再用干净的铲子铲起1cm～2cm厚的足迹土,连同感染的纱布一并提取装在封闭的磨口瓶内(纱布仍覆盖在沙土上),然后将磨口瓶放在无腥味的开水瓶口上适当加湿,当瓶内稍出现水珠时即停止.用时将沙土及纱布取出,效果较好     

Estimation of stature from footprint and foot outline dimensions in Gujjars of North India

Estimation of individual's stature is an important parameter in forensic examinations. Examination of footprints provides important evidence in a crime scene investigation and helps in estimation of stature of a criminal. Analysis of bare footprints is often carried out in developing countries like India where the footprints are frequently recovered at the scene of crime. The present study attempts to reconstruct stature in a sample of 2080 bilateral footprints and foot outlines collected from 1040 adult male Gujjars of North India ranging in age from 18 to 30 years. Bilateral footprints and foot outlines of each individual were measured for ten and eight measurements, respectively. The results indicate that T-2 length (length of the footprint from heel to 2nd toe) and T-5 length in footprint and T-1 length, T-4 length and breadth at ball in foot outline show statistically significant bilateral asymmetry. Significant and positive correlation coefficients exist between stature and various measurements of footprint and foot outline (P<0.001 and 0.01) except toe 1-5 angle of declination which shows insignificant correlation coefficient. The highest correlation coefficients were shown by the toe length measurements (0.82-0.87) indicating a close relationship between the stature and these measurements. Regression analysis presents smaller mean errors (2.12-3.92cm) in estimation of stature than those of division factor method (3.29-4.66cm), thus, gives better reliability of estimate than the latter. The regression equations were also checked for their accuracy by comparing the actual stature with estimated stature.     

Sex differences in proximal humeral outline shape: elliptical Fourier functions

A method is presented for the numerical analysis of sex differences in size and shape of the proximal humeral outlines using elliptical Fourier functions (EFFs). A skeletal sample consisting of right and left humeri pairs of 69 individuals, 36 males and 33 females, was used. The proximal superior view in the plane of the proximo-distal axis of each humerus was photographed and then 54 boundary points were located on the two-dimensional outline tracings. These points were digitized and used to compute EFFs with 27 harmonics. From the EFFs, a set of expected points on the proximal humeral outline was generated using the centroid as an origin. Superimposition of the male and female outlines on this centroid provided a detailed picture of the relative sex differences in size and shape with respect to that center. The bounded area of the proximal humeral outline showed statistically significant sex differences. Additionally, statistical results of the amplitudes derived from the "area-standardized" EFFs and visual assessments of the mean outline plots indicated significant sex differences in shape of the proximal humeral outlines. Focusing on localized regional differences, the greater tubercle was located more postero-medially and the lesser tubercle was located more anteriorly in the males compared to the females. Sex determinations from the proximal humeri were also examined with discriminant functions based on the amplitudes, which represent shape characteristics of the outline, and the hounded area. Using a cross-validation method, predictions of the percentages of cases correctly classified with the discriminant functions were ranged from 92.8% to 95.7% for the right and left humeral data. These results suggest that differences in size and shape of the proximal humeral outlines may be better predictors of sex when compared with conventional measurements of the humerus.     

油墨捺印赤足迹的稳定性研究

目的探讨使用油墨法捺印赤足迹样本的稳定性;方法用图像处理方法得到油墨赤足印的轮廓,计算机软件测量特征尺寸,用统计学方法分析数据;结果特征尺寸偏差≤4mm;结论油墨捺印方法能够稳定、客观地反映足迹特征。     

Human Identification via Lateral Patella Radiographs: A Validation Study,

This research examines the utility of patella outline shape for matching 3D scans of patellae to knee radiographs using elliptical Fourier analysis and subjective methods of human visual comparison of patellae across radiographs for identification purposes. Repeat radiographs were captured of cadaver's knees for visual comparison before patellae were extracted and skeletonized for quantitative comparisons. Quantitative methods provided significant narrowing down of the candidate pool to just a few potential matches (<5% of original sample), while the human analysts showed high capacity for correctly matching radiographs, irrespective of educational level (positive predictive value = 99.8%). The successful computerized matching based on a single quantified patella trait (outline shape) helps explain the potency achieved by subjective visual examination. This work adds to a growing body of studies demonstrating the value of single isolated infracranial bones for human identification via radiographic comparison.     

Roentgen imaging of stab wounds in parenchymatous organs

Stab wounds were made in parenchymatous organs (e.g. liver, spleen, kidneys, lungs) using a variety of instruments. The shape of the resulting canal was investigated by X-ray analysis after introduction of an X-ray contrast medium. The best contrast was obtained using a contrast medium containing barium. The shape of the canal gave a direct representation of the outline of the instrument used. The width of the canal was however, always several millimeters smaller than the corresponding blade of the instrument. The position of the blade back in single-edged blades could be demonstrated with stronger contrast.     

Characteristics of stab wounds inflicted by knives with the gear-sharpened blade

The authors present the results of an experimental study designed to estimate the damage to biological and non-biological objects inflicted by the knife blades having the gear-type sharpening. It was shown that a knife with such sharpening leaves edges of the damage of characteristic shape and outline. The results of the study testify to the expediency of further studies on the damaging action of knives considered in the present paper.     

Sexual Dimorphism of the Fetal Ilium: A 3D Geometric Morphometric Approach with Multislice Computed Tomography

Adult sexual dimorphism is well established. However, data regarding fetuses are sparse with contradictory results. Our study aimed to look for fetal sexual dimorphism. Multislice computed tomography (MSCT) examinations and three‐dimensional (3D) reconstructions were recorded on 93 fetal iliac bones aged between 21 and 40 weeks of amenorrhea (WA). The collection was divided into two age groups, with a cutoff at 30 WA. The 3D geometric morphometric analysis was based on outline analysis. We used elliptic Fourier analysis (EFA) because of the difficulty of landmark positioning. Step‐by‐step reconstructions allowed a better comprehension of the fine shape details. Principal component analysis (PCA) and linear discriminant analysis (LDA) were performed on the two age groups. Results did not show any difference between male and female shapes, in both age groups. We demonstrate the feasibility of outline analysis for immature shapes, but sexual dimorphism has not been established in our collection.     

Shoe wear patterns and pressure distribution under feet and shoes, determined by image analysis.

A method is outlined for extracting contours of the pressure exerted by feet on the ground, either directly or through the soles of shoes, and of the wear patterns on shoe soles. The method is applied to two types of image: shoeprint images made in the laboratory, and pedobarography images recording the distribution of pressure under the foot during a footstep. The first procedure in extracting the information from images involves low pass filtering in the Fourier domain, performed by a microcomputer and frame-grabbing system. The boundaries of the regions in the resultant images are then extracted from the filtered images to display the shape of constant pressure areas and of the general shoe-wear.