Simultaneous prediction of density and moisture content of wood by terahertz time domain spectroscopy

Inagaki et al. reported the use of effective medium theory for the prediction of density and moisture content from the complex permittivity values of wood in THz regions.

“Inagaki et al. [17] reported the use of effective medium theory for the prediction of density and MC from the complex permittivity values of wood in THz regions.”

Inagaki et al. extracted the volume fraction of each component from measured permittivity of wood after deciding the permittivity of each component in advance.

“They extracted the volume fraction of each component from measured permittivity of wood after they decided the permittivity of each of the components in advance.”

Inagaki et al. successfully performed simultaneous prediction of density and moisture content.

“Inagaki et al. [17] successfully performed a simultaneous prediction of density and MC.”

These methods are generally based on the linear relation between permittivity of wood and volume fraction of oven-dry wood cell wall, water, and air.

“As these methods are generally based on the linear relation between permittivity of wood and volume fraction of oven-dry wood cell wall, water and air, we simply and directly predicted the MC and density from measured permittivity or complex refractive index (in this study, we used real part of refractive index value and absorption coefficient) using multiple linear regression (MLR).”