Extraction of THz Absorption Signatures Obscured by Rough Surface Scattering Using Discrete Wavelet Transform

We investigate the effects of rough surface scattering on stand-off detection of materials using THz reflection spectroscopy. We apply discrete wavelet transform (DWT) to the normalized THz spectra to retrieve material absorption signatures obscured by the scattering effects. We address the impact of the non-zero phase functions of wavelet filters on the spectral location of the extracted resonant features and offer analytical solutions for compensating these phase effects.