Sheppard K, Fieldhouse S J, Cassella J P
Department of Criminal Justice and Forensic Science, School of Law, Policing and Forensics, Staffordshire University, Leek Road, ST4 2DF, United Kingdom.
Sci Justice. 2019 Jan;59(1):75-82. doi: 10.1016/j.scijus.2018.07.004. Epub 2018 Jul 24.
Forensic investigators frequently utilise light sources to detect and presumptively identify biological evidence. The instrumentation typically deploys single or multiple wavelength exposures at various intensities, which interact with constituents of biological material, initiating fluorescence or improving contrast between the material and substrate. Documentation using sketches and/or photographic approaches follows detection, which are essential for scene reconstruction. Recent research has demonstrated the simultaneous detection and capture of biological evidence using a 360° camera system combined with an alternate light source exhibiting broad wavelength ranges of light. Single wavelength light sources reportedly offer enhanced sensitivity, due to the increased light intensity and narrower bandwidth of light, although their combined use with a 360° camera system has not yet been explored. Samples of human blood, semen, saliva, and latent fingermarks were deposited on to a variety of substrates. A 360° camera system combined with a laser light source was used to detect and capture the samples. Ten participants were asked to detect the samples on images of the substrates without ground truth knowledge. It was possible to detect and capture biological evidence, although success varied according to substrate colour and light intensity. Advantageously, presumptive screening for biological fluids and the simultaneous location and visualisation of such evidence as part of a 360° panorama of the scene for contextual purposes was permitted. There was no fluorescent response from the fingermarks, although the oblique lighting effects appeared sufficient to aid mark detection in some circumstances. The use of single wavelength illumination clearly facilitates identification of a range of forensically important material. When coupled with a 360-degree camera, this allows for simultaneous identification and recording of such evidence in the context of the whole environment.
法医调查人员经常使用光源来检测并初步识别生物证据。该仪器通常会以不同强度进行单波长或多波长曝光,这些曝光与生物材料的成分相互作用,引发荧光或提高材料与底物之间的对比度。检测之后会采用草图和/或摄影方法进行记录,这对于现场重建至关重要。最近的研究表明,使用360°相机系统结合具有宽波长范围光的替代光源,可以同时检测和捕获生物证据。据报道,单波长光源由于光强度增加和带宽变窄而具有更高的灵敏度,尽管尚未探索其与360°相机系统的联合使用。将人类血液、精液、唾液和潜在指纹样本沉积在各种底物上。使用360°相机系统结合激光光源来检测和捕获样本。让10名参与者在不了解真实情况的前提下检测底物图像上的样本。尽管成功率因底物颜色和光强度而异,但仍有可能检测和捕获生物证据。有利的是,可以对生物体液进行初步筛查,并将此类证据作为场景360°全景图的一部分进行同步定位和可视化,以达到情境化目的。指纹没有荧光反应,不过在某些情况下,倾斜照明效果似乎足以辅助标记检测。使用单波长照明显然有助于识别一系列具有法医重要性的材料。当与360度相机结合使用时,这允许在整个环境背景下同时识别和记录此类证据。