Characterization of Electrical Tapes by Optical Coherence Tomography

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 arc extracted from the 2D cross-sectional OCT images of electrical tapes. Statistically significant differences of the parameters arc 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.