| As an essential material reserve for survival and development of mankind,grain plays a critical role in the maintenance of social stability,protection of people’s livelihood and national development.At present,the average loss rate of stored grain is about 0.2%-0.5% every year in our state treasury,insect damage was a significant cause of the phenomenon.Therefore,the detection technology of stored grain insect has been the focus of the state administration and industry of grain.As one of the scientific decision for avioding insect damage in grain storage,the detection data of grain insects is of great significance to ensure the quality of stored grain.The main contents of the paper are as follows:(1)Based on the review of domestic and overseas detection of stored grain insects,the main methods of measuring insects and the drawbacks of the existing methods have been introduced and analyzed.Be inspired by the sensing technologies in liquid analyze fields,a capacitive insects detection approach has been proposed creatively.(2)The holistic framework of the insect monitoring system has been designed,and the functional analysis of the core components of the system has been achieved.(3)There’s no sensor device can be directly used in the market as that the detection of p F-level capacitance has not been in scale.After comparing and analyzing the merits and demerits of several detection approaches,AD7151 chip has been used as the core device,the hardware structure and work flow of the mobile detection device was designed.The principle of the detection module has been expounded.The design of detection capacitance structure,the circuit and the software of the detection module have been carried out.The component selection and design of communication scheme were introduced.(4)Six kinds of common grain insect have been selected as sample and the data were collected by using an experimental device.Aiming at the characteristics of the data,the feature part of the data has been extracted by using extreme value mark and monotonicity detection,etc..On the basis of the contents discussed above,the model curves of grain insects are established.Then a method of calculating the Fréchet distance of discrete curves was designed,and the Fréchet distance of the measured curve and the model curves are calculated respectively,the similarity degree and similarity probability between the measured curve and the template are evaluated,and the results showed that the method are effective in detecting different kinds of grain insects.(5)Using C# language,the software of the upper computer interface of the system has been developed on the platform of Microsoft Visual Studio,and the functions of data collecting,summarizing,arranging and displaying have been achieved.Users can interact with the bottom hardware through the upper computer interface.Then the performance of the system has been tested based on the several common indexes. |
