Scattering-independent glucose absorption measurement using a spectrally resolved reflectance setup with specialized variable source-detector separations

Specialized source-detector separations in near-infrared reflectance spectroscopy platform enable effective separation of diffusion and absorption for glucose sensing

“…If only the scattering varies, then ρ * could be a scattering variation-independent SDS (SVI-SDS) [12].…”

“…A variety of reports have focused on the analysis of the scattering and absorption sensitivities of diffuse reflectance with different SDSs [7][8][9][10][11][12][13]. These studies showed that the characteristics of the scattering sensitivity vary with the chosen SDS.…”

“…First, for small SDSs, the optimal sensitivity of scattering can be obtained where the largest reflected light intensity is observed. As the SDS increases, the scattering sensitivity continues to decrease until a particular value of the SDS is reached, at which the scattering sensitivity becomes zero [7,8,10,12,13]. This SDS is called the scattering variation-independent SDS (SVI-SDS) [12] and denotes the point at which the diffuse light intensity no longer varies with the scattering variation of the medium.…”

“…As the SDS increases beyond the SVI-SDS, the scattering sensitivity increases again, opposite to its prior behavior. The absorption behavior typically exhibits a continuously increasing trend with SDSs [12,13]. Some components cause scattering and absorption changes simultaneously, and their measurement shows a combined result.…”

“…We previously proposed an approach for separating them by using SVI-SDS [13]. At the SVI-SDS, there is not scattering change information; however, the absorption signals can be obtained [12]. Nevertheless, for glucose sensing, the reserved glucose absorption signals appeared weak and were inadequate for desired accurate sensing for some used wavebands.…”