红外光谱微量水平衰减全反射技术检验常见胶水的应用研究

目的建立无损快速检验胶水红外光谱法。方法利用红外光谱衰减全反射技术（ATR）对8种常见胶水样品进行光谱分析,根据出峰位置差异,对8种胶水样品进行鉴别,并建立相应的红外光谱数据库。结果不同类型的胶水其红外图谱有明显差异,而同一类胶水在某些波数区间也存在着一定的差异。结论利用红外光谱衰减全反射技术可以快速、准确、无损的检验鉴别胶水样品。     

傅里叶红外图像无损检验添改数字的研究

目的建立利用傅里叶红外图像系统无损检验添改数字的检验方法。方法采集同种同品牌、同种不同品牌及不同种书写材料书写的数字1改为4和3添加为8两类样本的红外图像，根据红外吸收的光谱信息对其添改进行检验。结果同种不同品牌及不同种书写材料对红外吸收强弱不同，形成的红外图像有差别；同种同品牌书写材料对红外吸收强弱没有明显差别。结论该检验方法不损坏检材，重现性好，并且纸张成分对其分析结果基本上无干扰。     

显微共焦拉曼光谱法在添改文件检验中的应用

随着经济犯罪和民事纠纷案件的日益增多,针对合同、票据、文件中的某些文字是否添改形成的检验给司法工作者造成一定的麻烦,因此如何快速、准确、无损进行检验显得尤为关键。文献报道过用色谱法对签字笔墨迹进行鉴别,但都破坏了样品,无法满足物证的无损检验要求。显微共焦拉曼光谱法分析速度快,对样品无需处理就可直接进行无损检测,     

活用磁性粉解决痕迹拍摄中的困难

我们日常工作中常用磁性粉来刷显汗液指纹,但它不仅仅只是这一个用途。从磁性粉的特性出发,它还可解决痕迹拍摄中一些比较麻烦的环节。1解决“502”胶熏显指纹拍摄的难度用“502”胶熏显存在于不平整的彩色底板上、弯曲度较大的高光表面上(玻璃瓶、硬塑瓶、不锈钢管等)的指纹,在拍摄操作中用定向反射、掠入射、侧光照明等方法均很难取得良好的成像效果,紫外、红外、染色等照相方法也同样未能很好的解决问题。笔者用800目的磁性粉得到较好效果,将其轻刷胶体指纹的表面,使磁性粉粘于胶体上,然后吸去过厚或杂乱的磁性粉,再用胶带纸顺着指纹所在…     

基于数据挖掘算法的骨盆损伤判别模型

目的 利用主成分分析、偏最小二乘法对基于骨盆CT图像提取的特性信息进行降维,利用降维的数据建立判别骨盆是否受伤的支持向量机分类判别模型,评估其应用的可行性。方法 将采集的正常和受伤骨盆CT图像146例分别随机提取80%作为训练集,用于模型拟合;剩余20%作为测试集,用于模型准确性的检验。通过CT图像输入、图像预处理、特征提取、特征降维、特征选择、参数选择、模型建立和模型比较等步骤,建立骨盆是否受伤的判别模型。结果 偏最小二乘法降维方法优于主成分分析降维方法,支持向量机模型优于朴素贝叶斯模型。基于12个偏最小二乘因子建立的骨盆是否受伤支持向量机分类判别模型的建模集、留一法交叉验证和测试集结果准确率分别为100%、100%和93.33%。结论 基于CT图像建立的骨盆是否受伤数据挖掘模型在评估骨盆损伤中具有比较高的准确性,为骨盆损伤的自动快速识别奠定基础。     

近红外照相显现深色衣料上血迹的实验研究

目的运用近红外反射照相技术,显现深色衣料上的全血及稀释血迹。方法取单个体人全血,用纯净水分别以1∶4、1∶8、1∶16、1∶32比例稀释,并立即将稀释血及全血分别滴落在10种组份共21块深色衣料上,使其自然干燥形成血迹,用普通数码相机及专业红外数码相机,分别对血迹进行拍照获取彩色图像及红外黑白图像。结果红外照相显现血迹优于彩色图像;不同衣料相同浓度稀释血迹的红外图像存在差异;相同衣料不同浓度血迹的红外图像亦有所不同。结论近红外红外照相可以很好地显现深色衣料上的血迹,血迹的红外图像形状有助于判断是否为稀释血液所形成;血液浓度对红外显现结果的影响较大。     

FTIR法检验海洛因中的淀粉、葡萄糖、蔗糖

目的建立检验掺有淀粉、葡萄糖、蔗糖的海洛因的新方法。方法红外光谱。结果给出了用FTIR检验掺有淀粉、葡萄糖、蔗糖的海洛因的判据。结论用红外光谱法可以准确、无损鉴定掺杂淀粉、葡萄糖、蔗糖的海洛因。     

付立叶红外显微镜及其附件检验微量纤维

通过付立叶红外显微镜及其附件ATR、金刚石池对微量纤维进行检验,从而达到对微量或痕量纤维准确确定其种属和比对检验是否相同的目的,方法准确、快捷、可靠.     

利用傅立叶变换红外光谱技术快速检验静电复印纸

目的建立一种利用傅立叶变换红外光谱技术快速检验静电复印纸的新方法。方法采用傅立叶红外光谱仪对近似静电复印纸进行了快速检验,同时分析了新方法的技术特点。结果采用本文所述的方法可以对近似静电复印纸进行准确的快速检验。结论利用红外光谱技术检验纸张是一种较新颖的,快速、灵敏、准确的纸张检测技术,能对纸张的品牌种类,甚至批次进行鉴别,对大量样本鉴别和碎小纸片鉴别尤其适用。     

全波段CCD在紫外反射照相中的应用

1 系统简介 全波段CCD物证检验系统是一套紫外、可见光、红外图像高分辨率实时显示和专业图像处理设备。它可将不可见光图像实时转化为可见光图像，并可实现低照度情况下微弱信号的采集以及高质量图像的采集和处理，集痕迹检验、文件检验、数字照相和图像处理于一体。     

Use of lycode powders for the examination of documents partially written with erasable ball point pen inks

It was discovered by change that lycode powders adhere to erasable ball point pen ink strokes. A study of this phenomenon was carried out to determine what type of inks reacts physically with lycode powders. A further evaluation was made to learn if this effect continued after the erasable ink became indelible. It was also found that obliterated erasable ball point pen ink can be read by applying lycode powders and that the powders react in a similar way with typewriting from a conventional inked typewriter ribbon. Treatment in this case is completely non-destructive since the lycode powder can be wiped off the paper surface.     

纳米粉末显现水果和蔬菜表面手印

目的研究纳米粉末显现水果和蔬菜表面的手印。方法纳米Fe3O4粉末的显现方法同常规磁性粉末;纳米ZnO粉末则是撒粉于可疑表面,然后用吸耳球轻轻吹掉多余的粉末直到手印显出,利用多波段光源,在紫外一可见光范围内拍照;并与松花粉显现法比较。结果纳米Fe3O4粉末可以清晰显现4种检材表面的手印;纳米ZnO粉末可显现除土豆之外的3种检材表面的手印,尤其显现西红柿表面手印的效果最好;与松花粉相比,纳米粉末显现的手印纹线流畅、细腻,细节特征清晰。结论利用纳米粉末可以有效显现水果蔬菜表面的手印,显出的纹线在紫外－可见光范围内拍照均可以得到反差较大的影像。     

A discrimination method for paper by Fourier transform and cross correlation

A non-destructive method for discriminating between different types of paper has been proposed, using image analysis, Fourier transformation, and cross-correlation matching. A fast Fourier transform (FFT) is used to extract the periodicity in the structure of paper that results from the manufacturing processes. The light-transmission images of the paper to be Fourier transformed are obtained from a flatbed image scanner. The similarity between the power spectrum of the FFT of the sample and that of a reference is quantified using a cross-correlation matching method. An advantage of using frequency analysis is that periodicity can be detected even if the sample is damaged or is printed on. The technique works on samples as small as 2 cm2.     

The transference of patterns printed or indented on a sheet of paper to a plastic surface

Experiments have been made in which the image of Xerox-letters printed on a sheet of paper is transferred to a sheet of plastic and developed by dusting. The sheet of paper is sandwiched between two sheets of plastic, which are pressed between two flat metal plates by a mechanical press. After removing the pressure, the sheet of plastic facing the letter-printed surface of the sheet of paper is separated or torn from the paper using electrically insulated forceps. Then by sifting fine alumina powder onto the plastic surface, a dust figure can be obtained. This figure shows the transcribed letters corresponding to the original Xerox-letter on the sheet of paper.By this method, indented letters, or letters drawn with ink on a sheet of paper, or a fingerprint impressed on a sheet of paper can be transcribed onto the surface of a sheet of plastic.     

Imaging electrostatic fingerprints with implications for a forensic timeline

The electrical charge deposited by contact electrification due to a finger touching a thin insulating surface is imaged using an electric field microscopy system. It is based on an ultrahigh impedance electric potential sensor used as a non-contact raster scanning probe to measure surface charge density with a spatial resolution of up to 5 μm. Preliminary results are presented which yield two principle findings. First, they indicate that the spatial resolution of the fingerprint image is sufficient for identification purposes. Secondly, that the decay of the surface charge may be considered as a candidate method for the dating or sequencing of these electrical charge fingerprints. The decay of surface charge with time is well defined, largely material dependent, and may take many days. This intrinsic decay rate for the material may be quantified using the charge imaging system described in this paper and a known test charge. The measurement technique described is non-destructive, may be repeated without degradation of the sample, and does not preclude the subsequent use of other techniques such as DNA analysis or conventional latent fingerprint development.     

傅立叶变换红外光谱法检验口红的研究

目的建立一种灵敏、准确、无损的口红检验方法。方法利用傅立叶变换红外光谱仪,采用SmartPerformer采样器,对202个不同产地、不同品牌和同一品牌不同牌号的口红样品进行分析检验。结果依据红外光谱图中吸收峰的不同,可以将口红样品加以区分。结论该检验方法不破坏检材,重现性好,可用于鉴定案件现场中提取到的口红物证。     

An esoteric technique useful in the identification of unidentified remains from the examination of faded,illegible hospital identification wristbands

A technique routinely used in the examination of questioned documents has been found to be of assistance when employed in the examination of faded and/or partially legible hospital identification wristbands found with unidentified remains (UIDs). A non-destructive test used predominately by forensic document examiners in the analysis of writing inks, handwritten alterations, and obliterations has proven useful throughout the years when confronted with this unusual type of documentary evidence. This discussion paper was prompted by the Tri-State Crematory disaster, Walker County, Georgia, from a request by investigators as to whether or not any information could be obtained from the examination of faded hospital identification wristbands where no information was readily discernable. Subsequent analysis by non-destructive infrared inspection, a standard technique used in the examination of questioned documents, proved useful in assisting with the identification of unidentified skeletal remains.     

Gelatine lifting, a novel technique for the examination of indented writing

The limitations of the examination of indented writing impressions using electrostatic detection are often paper related. Paper types such as glossy paper, paper of high basis weight, and lithography or gravure-printed papers often give rise to problems resulting in a decrease in sensitivity or a lack of detection altogether. In this paper, a novel technique for the examination of indented writing is presented, which is in a sense complimentary to the technique of electrostatic detection as it is especially suitable for glossy-coated and printed paper types and can in some instances also deal with paper types of higher basis weight. Indented writing grooves will normally contain more particles than the surrounding nonindented areas due to damage of the surface layer resulting in a build-up of filler powder. The method presented uses black gelatine lifter slabs to lift the paper dust image off the surface of the paper. This image can quite easily be photographed using near-to-coaxial lighting. The gelatine lifting method outperforms oblique lighting for the detection of indented writing and is almost as sensitive as electrostatic detection if compared on the types of paper where both perform well. The main advantage of this new technique is, however, that it is especially suitable for those types of paper where electrostatic detection fails and is therefore a welcome addition to the range of methods available to a forensic document examiner for the examination of indented writing.     

Development of Latent Fingermarks on Various Surfaces Using ZnO‐SiO2 Nanopowder

Fingermarks are one of the most useful forms of evidence in identification and can provide generalized proof of identity in crime investigation. They are developed using various conventional powders. The novel nanopowder ZnO‐SiO₂ was synthesized via the conventional heating method and characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), energy‐dispersive X‐ray (EDX) analysis, transmission electron microscope (TEM), and X‐ray diffraction (XRD). The mean particle size of ZnO‐SiO₂ nanopowder calculated through TEM was 32.9 nm. The development of fingermarks was carried out by powder dusting and small particle reagent (SPR) methods. Powder dusting method was used for the development of latent fingermarks on various dry, nonporous, and semi‐porous surfaces. The SPR method was also applied to wet nonporous surface. The developed latent fingermarks using ZnO‐SiO₂ nanopowder were found to have excellent quality with very clear third‐level ridges detail and had better visibility than commercially available white powder.     

The detection and enhancement of latent fingermarks using infrared chemical imaging

The use of a new technique, Fourier transform infrared (FTIR) chemical imaging, has been demonstrated for the enhancement of latent fingermarks on a number of surfaces. Images of untreated fingermarks on glass backgrounds with excellent ridge detail were acquired using infrared chemical imaging. High quality fingermarks on glass backgrounds were also developed using ethyl cyanoacrylate (super glue) fuming and subsequent infrared chemical imaging. This new method allows the collection of images from backgrounds that traditionally pose problems for current fingermark detection methods. The background may, for example, be highly colored, have a complex pattern, or possess other pattern or image characteristics that make it difficult to separate fingermark ridges using traditional optical or luminescent visualization. One background that has proven to be a challenging surface for the development of latent fingermarks is the Australian polymer banknote. To demonstrate the power and applicability of infrared chemical imaging, fingermarks fumed with ethyl cyanoacrylate were successfully imaged from Australian polymer banknotes.