The fast and reliable detection, segmentation and visualization of latent fingerprints are the main tasks in forensics. Currently, conventional fingerprints are searched for, recorded and subsequently analyzed via traditional destructive physical and chemical methods. For firmly defined crime objects and undefined crime scenes, the forensic process is very time-consuming and can take several hours for a single fingerprint. In this context, a laser-based measurement technique that records complete latent fingerprints under fifteen seconds in a non-destructive manner was developed that digitizes the fingerprint for postprocessing steps. The optical system is based on confocal measurements in the mid-infrared wavelength range (2 μm–4 μm) to analyze specific chemical substances at crime scenes. The resulting chemical segmentation allows molecule-dependent analysis of latent and visually invisible fingerprints, providing clear conclusions about the perpetrator or the course of the crime. In this study, the application of the developed measurement system (MIR scanner) to capture fingerprints in a molecule-dependent manner within few seconds is demonstrated, compared with reference methods such as FTIR (Fourier transform infrared spectroscopy) imaging, and extended to real crime objects.

中文翻译：

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通过新颖的中红外扫描方法对潜在指纹进行快速化学检测和分割


快速可靠地检测、分割和可视化潜在指纹是法医的主要任务。目前，通过传统的破坏性物理和化学方法搜索、记录和随后分析常规指纹。对于明确定义的犯罪对象和未定义的犯罪现场，取证过程非常耗时，并且可能需要几个小时才能获得一个指纹。在此背景下，开发了一种基于激光的测量技术，该技术可在 15 秒内以非破坏性方式记录完整的潜在指纹，将指纹数字化以进行后处理步骤。该光学系统基于中红外波长范围 （2 μm–4 μm） 的共聚焦测量，用于分析犯罪现场的特定化学物质。由此产生的化学分割允许对潜在和视觉不可见的指纹进行分子依赖性分析，从而提供有关犯罪者或犯罪过程的明确结论。在本研究中，与 FTIR（傅里叶变换红外光谱）成像等参考方法相比，展示了开发的测量系统（MIR 扫描仪）在几秒钟内以分子依赖性方式捕获指纹的应用，并扩展到真实的犯罪对象。