Improving Detection Limit of Non-Dispersive Infrared Gas Sensor System by Wavelet Denoising Algorithm

摘要

The improvement of the detection limit of gas sensors has always been the focus of sensor research. Compared with theimprovement of hardware, the improvement of the algorithm is still relatively less. In this study, a dual-channel methanegas sensor system based on mid-infrared LED light source was designed. We apply the wavelet denoising algorithm tothe high-frequency noise suppression of the sensor system, which achieves a 36dB signal-to-noise ratio improvementover the traditional low-pass filter, making the detection limit of the sensing system reach the level below 3ppm. Wegive an estimation method for the detection limit of the sensing system. The detection limits estimated by this theory arebasically the same as those obtained by the Allen deviation analysis in the conventional method. Implementing betteralgorithms to improve sensor SNR in software can reduce the demands of improving sensor SNR solely from hardwareimprovements.