Research On Synchronous Spectral Measurement Methods Of Blood Glucose Under Multi-Wavelength

In the time sharing measurement of blood glucose with multi-wavelength,it is difficult to eliminate the disturbance of light source drift and measuring condition variations which are not synchronized to different wavelengths.And the stability of spectral data is influnced.Therefore,a synchronous measurement scheme is designed for the simultaneous measurement of blood glucose spectra with the application of lockin amplifier,spectrum transformation and virtual instrument technology: the multi wavelengths light signals are modulated into sine waves in different frequencies,and then mixed into a superposition signal.After measuring the objects,the sine waves' amplitudes are demodulated from the superposition signal with weak signal detection technology.Therefore the synchronous and precise spectra measurement under multiwavelength is realized.In order to realize the simultaneous spectra measurement of blood glucose under multi-wavelength,the related knowledge of weak signal detection technology is introduced at first,based on which three methods to demodulate sine waves from the superimposed signal are designed.The methods are respectively frequency selective with analog signal,orthogonal vector's lock-in amplifier(abbreviated as OV-LIA)and spectral transformation with digital signal.Then the design ideas and principles of the three methods are introduced in detail,according to which the frameworks of synchronous blood glucose spectra measurement system are constructed.Meanwhile the error sources of the three methods are analyzed and compared.Then the blood glucose synchronous measurement system is constructed.The LabVIEW platform is applied to simulate the experiment and verify the feasibility and effectiveness of the methods.At the same time,the influence of system parameters on the system performance is studied and determined.Therefore the system is built according to the theoretical simulation results and block diagrams.And the modules of the system is introduced.Finally,the comprehensive performance of each method is verified and evaluated experimentally.Debugging is conducted and the light source drift and dark noise of the detector are measured.Then the accuracy,reproducibility and linearity of the three methods are tested on standard reflecting plates.Meanwhile,the demodulation effects of the three methods are compared.In the end,the sensitivity of the system under OVLIA method is studied on the Intralipid-glucose solution.Based on spectral transform method,the advantages of spectral synchronization measurement compared with timesharing measurement in eliminating disturbance in human experiments are studied.The experiment results show that the blood glucose spectra simultaneous measuring methods under multi-wavelength can obtain the spectral data simultaneously and accurately,therefore effectively eliminate the influence of measurement conditions changing.And they are high in sensitivity and stability so as to realize the accurate weak signal simultaneous measurement with multi-wavelength.Especially for the OVLIA method and spectral transform method,in which the hardware structure are simpler.And they have the advantages of strong anti-interference capability,high reliability,easy debugging,flexible extensions,low cost,easy to transplant and so on,which provide a technical foundation for improving the performance of spectra measuring device and the miniaturization and personalized measurement of human body composition.