Wavelet Transform Smoothing Filters for Metal Oxide Gas Sensor Signal Cleaning

This paper reports on a series of experiments to evaluate the methods for feature extraction and denoising the digital signal from thin film zinc oxide-tin dioxide composite gas sensor devices. The aim was to find a method that not only cleaned the signal but also maintained the shape, precision and resolution of the signal. It was found that the Savitzky–Golay smoothing filter method gave the best, smoothed and cleaned, approximation of the sensor response regardless of the thin film composition, target gas concentration or operating temperature.