运用Photoshop软件进行形象痕迹检验

近几年来随着数字图像技术的快速发展,我们在实践中也逐渐将Photoshop运用于刑事科学技术领域的形象痕迹检验,运用电脑设备借助于数码相机或扫描仪,可以在不用显微镜等放大设备的条件下对指纹、足迹、工具痕迹、枪弹痕迹、文件材料进行直接检验,用于痕迹任意倍放大,方向、角度的调整处理,痕迹特征的描述、标注、比对、分析认定,并能直接打印出比对结果。笔者根据自己学习、使用Photoshop进行形象痕迹检验鉴定的实践,现以砍切工具痕迹检验为例将检验方法介绍如下。1检验操作方法根据工具痕迹检验的理论,利用成痕客体表面上反映成痕工具刃口…     

砍切工具痕迹样本制作及检验1例

工具痕迹检验一直是痕迹检验中的难点,一是痕迹样本制作难,二是比对检验难。工具痕迹样本制作的难点一是表现在选用材料上,其硬度、塑性要适当,既要能很好的反映工具的特征,又要不破坏工具的特征;二是要利于操作,能尽量模拟出与现场痕迹形成条件一致的作用方式。因此,合适的材料,对样本的制作会起到事半功倍的效果。比对检验难点表现在痕迹变化多,特征细、密,而比较显微镜视场小,难于定位。笔者在工作中发现“透明皂”是制作砍切工具痕迹样本的一种很好的材料,完全能满足上述二个条件,既经济又容易获得;样本制作完成后利用扫描仪转换成数码照片,与检材照片一同导人Photoshop图像处理软件,就可以直观地进行比对检验。     

人体骨骼上菜刀痕迹的检验及同一认定

目的 对人体骨骼上刀痕进行致伤工具同一认定的检验和研究.方法 用同一把菜刀的相同部位分别砍击骨骼与新鲜灌木,通过对骨骼上刀痕进行组织学处理以显现致伤工具的痕迹,并使用比对显微镜将骨骼与灌木上的砍痕进行比对,分析骨质断面的痕迹特征.结果 菜刀在骨骼上形成的砍切痕迹线条与比对样本的砍切痕迹线条可以完全拼接.结论 显微镜下可直观、清晰地观察到致伤工具在骨骼上留下的痕迹,为致伤工具的推断提供了新的方法.     

景深混合在痕迹检验中的应用

本文以三维视频显微镜观察采集多幅景深不同的弹壳底部痕迹图片,通过使用Photoshop软件中进行景深混合操作为例,将多幅相同视野大小、相同曝光参数、景深不同的痕迹图像,通过软件进行景深混合得到更大景深、更大清晰范围的痕迹图像,有利于提高枪弹痕迹检验工作质量。同时抛砖引玉,该方法可用于数码相机还有利用体式显微镜、立体显微镜等光学仪器的影像检验。     

《刑事犯罪痕迹物证检验图谱大全》征订信息

<正>《刑事犯罪痕迹物证检验图谱大全》是公安部刑侦局的组织全国刑侦系统近300名权威专家、技术骨干编纂的刑事科学技术专业大型工具书。图谱共12册,110万字,收录图片2.5万幅,涉及指纹、足迹、工具痕迹、枪弹痕迹、文件检验、法医、颅面识别、声纹、爆炸痕迹、交通工具痕迹等专业领域。是     

几类常见钥匙被增配使用后在母匙上形成痕迹的检验方法

目的研究几类常见钥匙增配痕迹特征分布。方法用光学显微镜观察钥匙的增配痕迹。结果几类钥匙的增配痕迹能够观察到。结论通过检验不同种类钥匙上的痕迹特征可以确定是否为增配使用痕迹。     

微量金属物证的扫描电镜/X射线能谱检验

金属物证是常见物证,在各类案件中都可能碰到,尤以盗窃案中为最多.作案使用的工具例如改锥、钳子、钢锯、以及配制钥匙等都会在现场造成微量金属的转移.传统的检验方法是用肉眼或光学显微镜进行痕迹比对.但扫描电镜具有光学显微镜所无法相比的优势,尤其对于粗糙样品,扫描电镜的数值孔径α一般在10~(-2)～10~(-3),其景深(D=200/aM)比光学显微镜要大几十到上百倍.扫描电镜更大的优势还在于观察痕迹形态的同时能对痕迹表面的附着物进行成份分析.大量的实验研究表明,物体相互受力形成痕迹的同时,总伴随着物质的相互转移,这种物质转移可能是作案工具与现场被破坏物体本身成份的转     

内凹齿钥匙痕迹特征研究

目的运用光学仪器研究内凹齿钥匙痕迹形态特征。方法制作内凹齿钥匙正常开锁和被钥匙机复制后的样本,用光学显微镜拍照固定痕迹特征。结果内凹齿钥匙开锁痕迹特征明显,且被钥匙机复制后能留下复制痕迹。结论通过检验内凹齿钥匙上的痕迹特征能确定钥匙是否被复制过。     

工具痕迹研究中的几个理论问题

近年来,尽管对工具痕迹的理论研究和实际应用已取得了较大的成果,但由于种种原因,在工具痕迹研究中还有一些基本理论问题尚未形成共识。诸如,工具痕迹的概念,工具痕迹的形成和分类,工具痕迹检验与手印检验、足迹检验的异同,工具痕迹学的研究对象和学科体系等等。由于理解和认识不一,以致在同类教科书中对相同的问题的论述相差很大,甚至互相矛盾,这既不利于工具痕迹学科理论框架的构建,也有碍于实际应用。笔者认为,有必要对这些问题作进一步的探讨,使之日臻完善。     

95式5．8mm自动步枪射击弹壳上痕迹的研究

目的研究95式5.8mm自动步枪射击弹壳上痕迹的检验价值。方法用10支95式5.8mm自动步枪分别射击50发,对收集的500枚射击弹壳在显微镜下观察测量。结果弹壳上痕迹反映普遍较浅,痕迹具有特殊性。结论95式5.8mm自动步枪射击弹壳上痕迹具有一定的同一认定价值。     

Three dimensional visualization and comparison of impressions on fired bullets

Currently, optical devices, such as microscopes and CCD cameras, are utilized for identification of bullets and tool marks in the field of forensic science. While these optical methods are easily manageable and effective, they are under great influence of illumination condition. In other words, appearances of striations through these optical devices have possibility to be changed by lighting condition. Besides these appearance-based approaches, we can utilize three dimensional (3D) geometric data of tool marks that are free from lighting condition. In this study, we focused on 3D geometric data of landmark impressions on fired bullets for identification. We obtained the 3D surface data of tool marks by a confocal microscope and reconstructed virtual impressions on a PC monitor from the geometric data. Furthermore, the 3D data are exploited to numerical matching of two surface shapes. We also visualized the difference of two shapes. In order to do this, two surface models are aligned automatically. In this process, pairings of correspondent points on both surfaces are determined. Distance analysis between these pairs leads to a shape comparison. Since comparison results are visualized, they are intuitive and easily perceptive.     

Three-Dimensional Analysis of Cartridge Case Double-Casts

Due to the shot-to-shot variability in tool mark reproduction on fired cartridge cases, a method of replication is needed for the creation of training and testing sets. Double-casting is one method that has been used for this application, but the accuracy and variability of this method needs to be characterized. Three firearms were used to fire 25 cartridges each to create the master cartridge cases. The double-casting method consists of creating a silicone mold of the master cartridge case. A plastic resin mix is then poured into the mold to create the double-cast reproduction. Fifteen double-casts of each of the 75 fired cartridge cases were created across different silicone molds to analyze within- and between-mold variability. The master cartridge cases and double-casts were scanned with a confocal microscope (Sensofar® S neox) to create three-dimensional representations of the surfaces. Two similarity metrics were used for the objective comparison of the double-casts to their master cartridge cases: the areal correlation coefficient (ACCF_MAX) and the number of congruent matching cells (CMC). The ACCF_MAX and CMC data, along with visual examinations, showed that the double-casting method produces accurate reproductions. Within-mold variability was found to be minimal, and between-mold variability was low. These results illustrate that double-casting can be applied for training and testing purposes.     

Identifying Diagonal Cutter Marks on Thin Wires Using 3D Imaging

We present work on matching 2‐mm‐thick wires using optical 3D imaging methods. Marks on such small surfaces are difficult to match using a comparison microscope as this 2D imaging method does not provide height data about the sample surface. Moreover, these 2D microscopy images may be affected by illumination. Hence, the reference and investigated sample should be present at the same time. We employed scanning white light interferometry and confocal microscopy to provide quantitative 3D profiles for reliable comparison of samples that are unavailable for simultaneous analysis. We show that 3D profiling offers a solution by allowing illumination‐independent sample comparison. We correctly identified 74 of 80 profiles using consecutive matching striae (CMS) criteria, and we were able to match samples based on profiles measured using different 3D imaging devices. The results suggest that the used methods allow matching cutter marks on thin wires, which has been difficult previously.     

大鼠脑外伤后溶酶体酶Cathepsin—B和D的表达

目的研究大鼠脑外伤后溶酶体酶cathepsin-B和-D是否被激活及其不同时段表达变化,阐述其与凋亡执行因子caspase-3表达的关系,并探讨对脑外伤诊断及形成时间的意义。方法采用自由落体打击法建立脑外伤动物模型,并对模型及对照样本进行免疫荧光、双标和激光共聚焦检测,结果用SPSS10.0软件处理。结果脑外伤后1hcathepsin-B表达即增加,4～8d达高峰,脑外伤后32d仍处于高表达水平;cathepsin-D的表达于脑外伤后12h增加,4～8d达高峰,32d的表达仍然高于12h的表达水平。脑外伤初期,cathepsin-B和-D阳性细胞与caspase-3阳性细胞重叠较少,脑外伤后6h开始增加,32d仍然有很多阳性细胞重叠。结论脑外伤后cathepsin-B和-D被激活,其激活在脑外伤早期可能抑制细胞凋亡执行因子caspase-3的激活,之后(6h后)则与caspase-3起协同作用,共同促进细胞死亡;cathepsin-B和-D表达的时程变化对于脑外伤的法医学诊断和中晚期的时间推断有参考意义。     

Using Raman Spectroscopy to solve crime: inks, questioned documents and fraud

Raman microscopy is becoming a tool of major importance in forensic analysis, particularly of drugs and explosives. It is a non-invasive, non-destructive chemical probe allowing samples to be examined in their entirety without any preparation. This paper demonstrates the use of the technique as a general tool for inks analysis. Furthermore, it addresses two important issues that historically have been extremely difficult for the professional document examiner, namely, comparison of black ballpoint inks and the chronological sequencing of crossed ink lines. We show that Raman can successfully distinguish between a representative sample of commercially available black ballpoint inks. This data has been converted into a database for future reference. A method for chronological sequencing of crossed ink lines has been developed using confocal Raman microscopy. Case study work has shown the feasibility of this approach.     

Visualisation by confocal microscopy of traces on bullets and cartridge cases

The capabilities of confocal scanning laser microscopy for the visualisation of marks on bullets and cartridge cases were investigated. Confocal microscopy provides solutions to important limitations of conventional comparison microscopy with grazing light incidence, as generally used for the examination of these marks. It is expected that confocal microscopy, thanks to its broad applicability within the field of firearms investigation and its capability of non-destructively gathering quantitative three-dimensional information, will lead to a more complete and objective forensic examination of bullets and cartridge cases.     

二醋吗啡对大鼠心肌细胞游离Ca^2＋浓度的作用

目的观察二醋吗啡对心肌细胞内游离Ca2 浓度的作用。方法取自1～3d的SD大鼠培养的心肌细胞,用荧光探针Fluo-3/AM负载心肌细胞,不同浓度及不同剂量的二醋吗啡作用心肌细胞,激光共聚焦显微镜下检测Ca2 的变化。结果不同剂量及浓度的二醋吗啡对心肌细胞内游离Ca2 浓度有不同作用,一定浓度的二醋吗啡使心肌细胞内游离Ca2 浓度呈剂量依赖性的升高、短时间内心肌细胞[Ca2 ]i荧光强度增强,并产生[Ca2 ]i峰。结论探索出二醋吗啡导致心肌细胞内Ca2 变化的有效浓度,为进一步深入研究打下了基础。     

单细胞凝胶电泳检测大鼠死后肝细胞核DNA降解

目的应用单细胞凝胶电泳技术(SCGE)检测大鼠死后肝细胞核DNA降解规律,分析与死亡时间的关系,为早期死亡时间的推断提供新的方法。方法在大鼠死后30h内,每隔3h取肝组织样本进行单细胞凝胶电泳,用共聚焦显微镜摄取彗星图像,应用彗星图像分析软件(IM I1.0)进行图像分析,并作统计学分析。结果死后大鼠的肝细胞在电泳图像上出现明显的彗星形拖尾,其尾长(TL)、尾矩(TM)在一定的时间范围内(0~18h)随死亡时间的延长而逐渐增大,二者均与死亡时间(PM I)呈现一定的相关回归关系。结论单细胞凝胶电泳技术可应用于早期死亡时间的推断。     

Visualization of postmortem chondrocyte damage by vital staining and confocal laser scanning 3D microscopy

The present study was designed to investigate whether the combination of vital dyes [calcein acetomethyl ester and ethidium homodimer (LIVE/DEAD Viability/Cytoxicity Kit)] together with confocal laser scanning 3D microscopy was a suitable process to detect postmortem chondrocyte damage, and whether this process could be used to establish postmortem interval. Human knee cartilage from 13 autopsies (postmortem interval from 1 day to 2.5 months) was incubated with the two dyes. The chondrocytes revealed intense staining according to their vitality. For those cases that were stored mainly at 4 degrees C there was a vitality of approximately 88 to 96% within the first 4.5 days, which decreased to 58% after 6 days and to 9% after 1.5 months. After 2 days and 14 days at summer temperatures there were 70% and 8% vital chondrocytes respectively. Three of the 13 cases showed that altered body and storage conditions limited the efficacy of the method. Initial data suggested a time and temperature dependent increase in cell breakdown. Under stable cooling conditions the use of vital dyes and confocal laser scanning 3D microscopy to measure chondrocyte loss may be a valuable tool for estimating the postmortem interval.     

A method for studying knife tool marks on bone

The characteristics of knife tool marks retained on hard tissues can be used to outline the shape and angle of a knife. The purpose of this study was to describe such marks on bone tissues that had been chopped with knives. A chopping stage with a gravity accelerator and a fixed bone platform was designed to reconstruct the chopping action. A digital microscope was also used to measure the knife angle (θ) and retained V-shape tool mark angle (ψ) in a pig skull. The κ value (elasticity coefficient; θ/ψ) was derived and recorded after the knife angle (θ) and the accompanied velocity were compared with the proportional impulsive force of the knife and ψ on the bone. The constant impulsive force revealed a correlation between the V-shape tool mark angle (ψ) and the elasticity coefficient (κ). These results describe the tool marks--crucial in the medicolegal investigation--of a knife on hard tissues.