| In the non-invasive measurement of blood glucose using Near-infrared diffuse reflection spectroscopy,the blood glucose signal is weak and highly susceptible to background disturbances as instrument drift,variations of man–machine interfaces and physiological fluctuation in the body,etc.As a result,the blood glucose measurement is low in accuracy and limited in clinical application.The diffuse reflectance spectroscopy method based on position difference is considered as a promising method for non-invasive blood glucose concentration(BGC)measurement,which can effectively eliminate the influence of instrument drift.The choice of differential position is the key of measurement accuracy and the suppressing effect of human background interference.At present,the research on the selection of differential measurement positions is mostly based on experiments results of phantom solutions and simulation.The research of differential positions selection on human body is not sufficient.In this situation,a method for optimizing differential positions is proposed in this thesis.The results will help realize the extraction of truly useful blood glucose signals in human experiments.The main work of this thesis includes:At first,according to the requirements of photon detection depth by near-infrared non-invasive blood glucose detection,the first principle of differential position optimization is proposed: extracting effective glucose information.According to this,the first step of location optimization is to perform Monte-Carlo simulation of human skin to obtain a location area suitable for measuring the dermis layer.In order to improve the measurement accuracy of differential spectroscopy,the second principle of differential position optimization is proposed: to obtain the best differential sensitivity.Basing on the theory of near-infrared diffuse reflectance differential spectroscopy,the measurement location area is obtained that can achieve the best differential sensitivity is preferably selected.Aiming at the problem in actual measurement process that human body background changes affects the measurement spectrum,the third principle is proposed:human body background interference effectively suppressed.Among the optional positions satisfying the first two principles,the position with the closest differential distance should be selected as the final preferred result.In human experiments,artificially add two kinds of interference,namely skin temperature drift and measurement position jitter,which verifies the suppression effect on the interference of the differential spectrum on the selected location.Finally,the experimental results show that the preferred differential position in this paper can effectively suppress the interference in human body measurement and obtain the spectral signal synchronized with the change of blood glucose concentration.In this paper,the optimal strategy and results of human blood glucose measurement location using near-infrared diffuse reflectance differential spectroscopy are expected to be applied to practical non-invasive blood glucose measurement instruments. |
