Enhancing Environmental Noise Reduction in Photoacoustic Systems through Dual Microphone Exploitation

In this work we propose a method to reduce the environmental interference in resonant photoacoustic gas measurement system. The proposed solution exploits the signals acquired by two twin microphones integrated in the photoacoustic setup, one of which is oblivious with respect to the photoacoustic signal and captures only environmental noise. A Wiener filter with reverse approach is used to reduce the impact of noise on adj acent windows of the acquired photoacoustic signal, then the denoised frames are processed to extract the photoacoustic signal magnitude. The results obtained with the proposed procedure based on the exploitation of the twin microphone signals, and on digital processing are compared with experimental measurements based on analog processing, showing great advantage in reducing both background and spike noise in photoacoustic gas signal.