Extraction of glucose information in blood glucose measurement by non-invasive near-infrared spectra

摘要

Near infrared spectroscopy has been proposed as an effective way for measuring blood glucose non-invasively. However the change of spectrum due to an increase in glucose level is very small compared to the changes due to other variations such as absorption of major blood components, skin surface reflectance, temperature and pressure and so on. So the complexity of spectrum makes it difficult to identify unique glucose information. In this paper, the effect of background correction is discussed firstly. Then a simple substitution is proposed to compute the net analyte signal of glucose using the subspace spanned by the background spectra. For the in vitro experiment, the net analyte signals of glucose using the traditional methods and the subspace spanned by background have the same peaks in the absorption peaks of glucose for the glucose aqueous solution. For in vivo experiment, there is significant spectral difference between the subject who took OGTT test and the subject who took no glucose or water. And the net analyte signal of glucose is computed for OGTT test based on the subspace spanned by the spectra of subject who didn't take glucose. Results show that, the spectral information induced by glucose taking is quite significant but it does not have the same peak at the absorption peak of glucose in near-infrared region.