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材料表面粗糙度会影响太赫兹无损检测结果.当材料表面粗糙度在微波区可以忽略不计时,在波长更短的太赫兹频段则需要考虑在内.研究讨论了在太赫兹频率下粗糙表面散射对反射谱的影响.通过考虑单个样品的反射模型,利用基尔霍夫近似可以将粗糙表面的反射信号与光滑表面的反射信号进行关联.此外,采用太赫兹时域光谱(THz-TDS)系统对不同粗糙度的葡萄糖片进行了测量,并对其反射光谱进行了分析.反射光谱结果表明,由于表面粗糙度引起的漫散射减弱了接收端反射光谱的强度.为了减小粗糙度对光谱的影响,提出了一种能恢复光谱功率的补偿方法.在0.5 THz和1THz时,具有360目粗糙度规格样品的功率谱分别增加了约3dB和9dB.因此,可以认为所提出的粗糙表面光谱补偿方法在未来太赫兹无损检测技术的发展中具有一个特定的参考价值.“,”The roughness of the material surface affects the THz nondestructive testing results.Roughness of the surface can be ignored in the microwave region,but should be considered in the terahertz frequency domain.The effect of scattering caused by rough surface at terahertz frequency on the reflection spectrum was studied and discussed.By consideration of the reflection model of a single sample,the reflection signal of a rough surface can be correlated with that of a smooth surface by using the Kirchhoff approximation.In addition,the glucose tablets with different roughness were measured by THz-TDS (Terahertz time domain spectroscopy) system and their reflection spectra were analyzed.The reflection spectrum results show that due to the roughness of the surface,diffuse scattering generated by the rough surface weakens the intensity of the reflection spectrum at the receiver.In order to reduce the influence of the roughness on the spectrum,a spectral Gaussian compensation method was proposed,which can restore the spectral characteristics of the smooth surface.The power spectrum of 360 mesh roughness was increased by about 3 dB and 9 dB at 0.5 THz and 1 THz,respectively.Therefore,it can be envisaged that the proposed rough-surface spectral compensation method has a specific reference value in the development of the THz nondestructive testing technology in the future.