The wavelength-dependent characteristic of the floating-reference point in the non-invasive glucose sensing

摘要

In the noninvasive blood glucose sensing using near-infrared spectroscopy, the physiological noise was one of the biggest challenges. In order to efficiently reduce the influence of the physiological background variations on the diffuse reflectance spectra, the floating-reference method was used by differentially processing two signals from reference point and measuring point. In this paper, the wavelength-dependent characteristic of the floating-reference point was discussed by simulation and primary experiment. First, the wavelength-dependent characteristic of intralipid- 5% solution was investigated in the wavelength range of 1300-1600nm. And source-detector distance for reference point in the wavelength of 1300nm was conducted by different concentration of scatter media including 2%, 5% and 10% intralipid solution. Then the single-layer and three layers skin model were built to investigate the wavelength characteristic of reference point. The water displacement coefficients and relative large change in glucose concentration were considered in the simulation. Finally, the primary experiment of intralipid model was conducted to validate the wavelength dependence of reference point. The result showed that, the floating reference will not exist in the strong absorption region (near 1450nm) and the region where the change of absorption coefficient is positive (high than 1525nm) due to the corporate influence of scattering and absorption coefficient. And the wavelength-dependent characteristic is consistent for intralipid solution and the skin model.