Infrared Gas Detection System Research Based On Adaptive Interference Suppression Technology

In this paper, the subject studied comes from the national natural science fundproject "under the deep mining of infrared gas sensing properties change model andadaptive detection mechanism research（61307124）".Methane is a flammable and explosive gas, gas explosion accidents haveoccurred every year, which give people life and property safety brought great harm,so real-time monitoring methane gas is of great significance. There are many methodsto detect methane gas, such as catalytic combustion method, gas sensitivesemiconductor method, light interference method, infrared absorption method etc.Because many of the advantages of infrared absorption technology：Good selectivity,long life, good stability, high precision, wide measurement range, etc, using thetechnology to develop gas detector is the main measures of preventing gas explosion.In bad environment under the mine, however, the interference noise to the gasdetection is more, such as temperature, pressure, wind speed, a large mechanicaloperation of random noise sound pressure, circuit random noise, background lightrandom disturbance and so on, the more serious is that we are unable to predict thestatistical features of the noise, so we can’t adopt traditional filter method to filter outthe noise. Therefore, in the gas detection, this paper introduced the modern adaptivefilter, this method relies on the statistical characteristics of noise detection inestimates, real-time adjust the filter parameter, which can better the influence of thenoise. This for improving the performance of gas detector in coal mine environmenthas the vital significance.The main research content of this paper include: The first is to complete thewriting of the adaptive algorithm and simulation, verify the correctness of thealgorithm，it Proves that the adaptive algorithm has a good inhibition to the noise;Followed select appropriate light source and detector, and design the structure of airchamber, and finally complete the construction of the whole optical path structure. Secondly, design the hardware based on the principle of differential absorption overallblock diagram, complete each part of the design after welding and debugging; Afterusing data acquisition card and the LabVIEW software a platform adaptive methanedetection has set up, replacing the conventional using microprocessor to finish thesoftware of the signal processing methods. Finally, the adaptive detection platformfunction verification experiments, correlation analysis experiment and associated gastest are carried out, it has the further engineering application.The innovation of this paper:1. In gas detection, adaptive modern filter is introduced, this method relies on thestatistical characteristics of noise detection in estimates, real-time adjustment ofparameters of the filter, which can better the influence of the noise.2. Using the LabVIEW platform and PCI data acquisition card, adaptive methane gasdetection platform, built to verify the function of the platform, laid the foundation forthe further engineering application, it has the very good application value..