Template Matching-Based Method for Identifying Substances in Terahertz Spectrum

Aiming at the problem of mixture composition identification, terahertz time-domain spectroscopy is used to obtain the characteristic absorption spectrum of a substance, and the processing method of 0.1-7.0 THz wideband terahertz absorption spectrum and a method to identify its spectral characteristics arc studied. First, we deduct the influence of the environmental noise, background noise, and water vapor absorption spectrum changing with temperature change on the measured substance in the arc environment, and obtain the terahertz absorption spectrum for identification based on template matching, numerical smoothing, main absorption peak extraction and identification, followed by the determination of mixture components. We then establish a model for extracting and analyzing the terahertz spectra of the mixture components, refer to the terahertz spectrum database, use template matching, absorption peak to peak, and area comparison methods to sequentially determine and deduct the terahertz absorption spectra of each sample. Finally, based on the proposed algorithm model, the terahertz characteristic spectrum detection and identification of the mixed explosives arc achieved. Results show that the proposed method can sequentially distinguish the components of the mixture, and is a reliable method to identify the terahertz broadband spectral characteristics for these components.