Translation-Invariant Zero-Phase Wavelet Methods for Feature Extraction in Terahertz Time-Domain Spectroscopy.
Translation-Invariant Zero-Phase Wavelet Methods for Feature Extraction in Terahertz Time-Domain Spectroscopy.
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DOI：
10.3390/s22062305
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发表时间：
2022-03-16
期刊：
影响因子：
--
通讯作者：
Arbab MH
中科院分区：
文献类型：
--
作者：
Khani ME;Arbab MH
小波变换是太赫兹时域光谱（THz-TDS）测量计算信号处理的重要工具。尽管它的流行，使用不同形式的小波变换在太赫兹- tds研究的影响尚未调查。在本文中，我们探讨了使用最大重叠离散小波变换（MODWT）与众所周知的离散小波变换（DWT）的含义。我们证明了使用DWT提取的光谱特征可以在不同的重叠频率范围内变化。相反，MODWT是平移不变的，无论用于实现的光谱范围如何，都能得到相同的特征。我们还证明了使用MODWT的多分辨率分析（MRA）获得的细节系数与零相位滤波器相关联。相反，DWT细节系数受到DWT金字塔算法中上下采样操作引起的失调的影响。当保持吸收线的确切位置至关重要时，这种不对准会产生不利影响。我们利用-乳糖一水合物的反射THz-TDS测量，从分析和实验两方面研究了DWT和MODWT的差异。本文可以指导研究人员根据太赫兹光谱学的具体应用选择合适的小波分析工具。
Wavelet transform is an important tool in the computational signal processing of terahertz time-domain spectroscopy (THz-TDS) measurements. Despite its prevalence, the effects of using different forms of wavelet transforms in THz-TDS studies have not been investigated. In this paper, we explore the implications of using the maximal overlap discrete wavelet transform (MODWT) versus the well-known discrete wavelet transform (DWT). We demonstrate that the spectroscopic features extracted using DWT can vary over different overlapping frequency ranges. On the contrary, MODWT is translation-invariant and results in identical features, regardless of the spectral range used for its implementation.We also demonstrate that the details coefficients obtained by the multiresolution analysis (MRA) using MODWT are associated with zero-phase filters. In contrast, DWT details coefficients suffer from misalignments originated from the down- and upsampling operations in DWT pyramid algorithm. Such misalignments have adverse effects when it is critical to retain the exact location of the absorption lines. We study the differences of DWT and MODWT both analytically and experimentally, using reflection THz-TDS measurements of -lactose monohydrate. This manuscript can guide the researchers to select the right wavelet analysis tool for their specific application of the THz spectroscopy.
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影响因子：
4.6
作者：
Hsieh YD;Nakamura S;Abdelsalam DG;Minamikawa T;Mizutani Y;Yamamoto H;Iwata T;Hindle F;Yasui T
通讯作者：
Yasui T
影响因子：
2.2
作者：
Ferguson, B;Abbott, D
通讯作者：
Abbott, D
影响因子：
4.6
作者：
Khani ME;Osman OB;Arbab MH
通讯作者：
Arbab MH
影响因子：
3.9
作者：
Harris, Zachery B.;Khani, Mahmoud E.;Arbab, M. Hassan
通讯作者：
Arbab, M. Hassan
DOI：
10.1109/tthz.2020.2997595
发表时间：
2020-11
影响因子：
3.2
作者：
Khani ME;Winebrenner DP;Arbab MH
通讯作者：
Arbab MH