Real time infrared gas detection based on a modified EMD algorithm

Based on the analysis of the empirical mode decomposition (EMD) method, a modified algorithm for signal processing in IR optical gas detection has been presented. It extracts only the signal of interest instead of decomposing the input signal into all possible intrinsic mode function (IMF) components. In addition, a mean-envelope filtering (MEF) method is proposed to remove the unknown noise in the amplitude envelope obtained by the modified EMD (m-EMD). Experiments show that the detection precision is essentially improved. Besides, the algorithm has advantages of higher sensitivity and no “lagging” effect compared with the digital lock-in amplifier (DLIA). The performance of the algorithm offers a possibility of real time infrared gas detection.