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- 摘要
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- 实验方案
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Forensic Analysis - From Death to Justice || Usage of Infrared-Based Technologies in Forensic Sciences
摘要： Infrared (IR) radiation comprises a beam located in the electromagnetic radiation family; it arises from the thermal vibrations of radiation that have longer wavelengths than visible light, but shorter wavelengths than microwave radiation. Its wavelength is between 750 nm and 1 mm. The amount of thermal IR radiation emitted by an object is associated with the temperature of the object, the surface area of the object and the spreading of light. IR-based technologies have been demonstrated as a method of evidence identification in forensic sciences in addition to many daily uses. The combination of IR-based spectrophotometry with several techniques ushered in a new era in crime scene investigations and the identification of evidence obtained from crime scenes. Furthermore, the use of IR-based photography techniques has significant advantages. IR fluorescent automated DNA sequencer and thermal analyser for deception detection are other techniques that take advantage of IR technology. In this chapter, we aimed to present the IR-based technologies used in forensic sciences and forensic photography techniques to define the current situation, the importance and the advantages of IR thermal imaging among these techniques, as well as to describe the operating principles of IR thermal imaging technologies that may be generated in the future based on this technique.
关键词： Spectrophotometry,Scene Investigation,Post-Mortem Interval,Thermal Imaging,Infrared
更新于2025-09-23 15:21:01
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Gunshot residue on dark materials: a comparison between infrared photography and the use of an alternative light source
摘要： The pattern of gunshot residue (GSR) includes important information about muzzle-target distance since a larger GSR distribution diameter indicates a larger shooting distance. GSR may not be visible to the naked eye when, for example, it is located on dark textiles. In such cases, further procedures need to be performed in order to visualize the pattern of GSR. Besides chemical procedures, an alternative light source or infrared photography can be utilized for non-destructive GSR visualization. In the work presented, these two techniques are compared based on shooting experiments using 26 different dark textiles. Within the range of the alternative light source, the use of a 440-nm light in combination with an orange-colored filter led to the best visualization of GSR in the form of fluorescent particles. Infrared photography, on the other hand, visualized GSR as dark particles, whereas—ideally—the dark textile reflected the infrared light and appeared bright. The comparison of both techniques revealed that the GSR distribution visualized by infrared photography was not identical to the GSR distribution visualized with 440-nm illumination in combination with an orange-colored filter. We concluded that infrared photography visualizes the inner powder soot zone, whereas illumination at 440 nm leads to fluorescence of the outer powder soot zone, which can be visualized using an orange-colored filter. Knowledge of this difference in visualization of the two powder soot zones is important for forensic practitioners assessing firing distances. In the literature, however, this difference is not noted as clearly.
关键词： Gunshot residue GSR,Alternative light source,Forensic light source,Crime scene investigation,Shooting distance,Infrared photography
更新于2025-09-10 09:29:36