光学相干层析(OCT)技术是一种无损、高分辨率、快速的断层成像检验技术。电工胶带是法庭科学领域的一种重要物证。利用自主搭建的频域OCT系统对10种不同品牌的红色电工胶带进行OCT成像检验。从电工胶带的二维OCT图像中提取光程、散射强度比、信号峰个数、衰减系数等特征参数,比较各参数在不同样品之间的统计学显著性差异。对电工胶带样品进行三维OCT图像重建,获得样品的横截面图像。实验发现,上述特征可以有效区分不同品牌的电工胶带。OCT技术可以实现对物证样品的原位、无损、实时检验,且操作便捷、分辨率高,将为法庭科学电工胶带物证检验提供一种新的方法。

Optical coherence tomography (OCT) is a non-destructive, high-resolution,and fast tomographic imaging technique. Electrical tape is an important physical evidence in the forensic science. A self-built frequency-domain OCT system is employed to obtain two-dimensional (2D) cross-sectional OCT images of electrical tapes from ten different brands. The optical path, the scattering intensity ratio, the number of signal peaks, and the attenuation coefficient are extracted from the 2D cross-sectional OCT images of electrical tapes. Statistically significant differences of the parameters are compared in those different samples. Meanwhile, three-dimensional (3D) OCT image reconstruction of the electrical tapes is also implemented to create transverse sectional images beneath the surface. The experiments demonstrate that OCT provides a series of new features to effectively distinguish different brands of electrical tapes. OCT provides in-situ, non-destructive, high-resolution, and easily operated real-time examination, and it is a promising method for electrical tape examination in the forensic science.