Study On The Inversion Method To Extract Feature Value Of Smartongue Response Signal

Smartongue is a new type of electronic tongue system developed by our laboratory. It consists of sensor array, signal excitation-collection system and data processing system. The methods now use to extract the feature value of Smartongue response signal can’t completely extract the information it contents. So we need to find a new method to complete the information extract. According to the equivalent circuit analysis of solution, we found the inversion method to extract the Smartongue response signal feature value, used the MATLAB software to fulfill the code, proven the validity of the code by simulation. Finally, we applied the inversion method to Smartongue for beverage distinguishing. The research obtained the following conclusions:(1) Inversion method selection and code compilingAccording to the equivalent circuit analysis of solution, transient current of solution can be described by formula. Based on the description formula, combined with Smartongue excitation signal and response signal, we can use equations and matrix to express the instantaneous current of Smartongue respond signal. This kind of equations has common method to solve. According to the main idea of each algorithm, we use MATLAB software to transform the solving process into the code, make the data processing intelligent.(2) Analysis inversion method use modelBased on the instantaneous current formula, we used math simulation that without noise to make sure the inversion code is valid, and consider the total peak area as a feature value. At the same time, we used noisy math simulation to seek the application scope of the inversion method:SNRSIRT≥40dB, SNRSVD≥55dB, SNRNNLs≥70dB. Finally we used physical circuit to simulate the component number in solution, it shows that the inversion method can effectively calculate the component number.(3) The usability and discriminate ability of inversion method.We prepared3kind solutions:0.01mol/L potassium chloride solution,0.01mol/L sucrose solution,0.01mol/L sucrose and potassium chloride solution. Used electrochemical workstation to excite signal and collect data. From the distinguishing result, we can sure the availability of inversion methods.Used3kinds of beverage as the research object, we extracted the feature value of Smartongue response signal by inversion method, together with the vertex point and inflection point. We used data processing method to get the DI value of each method:85.95%(vertex-inflection method),87.76%(NNLS),88.09%(SVD),87.17%(SIRT). It proves that the inversion method to extract the feature value has effectiveness in distinguish beverage.In conclusion:this thesis implemented the inversion method code and analysis it’s applicable condition, then applied to smartongue to prove this method is good in distinguish.