King's Forensics, School of Population Health and Environmental Sciences, King's College London, 150 Stamford Street, London SE1 9NH, UK.
King's Forensics, School of Population Health and Environmental Sciences, King's College London, 150 Stamford Street, London SE1 9NH, UK.
Talanta. 2018 Jul 1;184:1-6. doi: 10.1016/j.talanta.2018.02.110. Epub 2018 Feb 27.
One of the most common tasks in criminal investigation is to determine from which tissue source a biological fluid stain originates. As a result, there are many tests that are frequently used to determine if a stain is blood, semen or saliva by exploiting the properties of certain molecules present within the fluids themselves. These include chemical reagents such as the Kastle-Meyer or Acid Phosphatase tests, as well as other techniques like the use of alternative light sources. However, most of the tests currently available have some major drawbacks. In this study, a handheld near-infrared spectrometer is investigated for the specific identification of deposited bloodstains. First, a calibration was carried out by scanning over 500 positive (blood present) and negative (blood absent) samples to train several predictive models based on machine learning principles. These models were then tested on over 100 new positive and negative samples to evaluate their performance. All models tested were able to correctly classify deposited stains as blood in at least 81% of tested samples, with some models allowing for even higher classification accuracy at over 94%. This suggests that handheld near infrared devices could offer great opportunity for the rapid, low cost and non-destructive screening of body fluids at scenes of crime.
在刑事侦查中，最常见的任务之一是确定生物体液污渍源自哪个组织来源。因此，有许多测试经常被用于通过利用液体本身中存在的某些分子的特性来确定污渍是否为血液、精液或唾液。这些测试包括化学试剂，如 Kastle-Meyer 或酸性磷酸酶测试，以及其他技术，如使用替代光源。然而，目前大多数可用的测试都有一些主要的缺点。在这项研究中，研究人员调查了手持式近红外光谱仪用于特定识别沉积血迹的用途。首先，通过扫描 500 多个阳性（存在血液）和阴性（不存在血液）样本进行校准，以基于机器学习原理训练了几个预测模型。然后，在 100 多个新的阳性和阴性样本上测试了这些模型，以评估它们的性能。所有测试的模型都能够正确地将沉积的污渍分类为血液，在至少 81%的测试样本中，有些模型的分类准确率甚至超过 94%。这表明手持式近红外设备可能为在犯罪现场快速、低成本和非破坏性地筛选体液提供了很好的机会。
