The effect of speckles noise on the Laser Doppler Vibrometry for remote speech detection

Speckles noise generated by the relative in-plane motion between the Laser Doppler Vibrometry (LDV) and the target damages the quality of the LDV-captured speech severely. As such, it is necessary to research on the effect of speckles noise on the LDV for remote voice detection and remove it. In this paper, we comprehensively discuss the statistical properties of dynamic speckles with the combination of theories and experiments, and the results show that the fluctuation of speckles intensity depends strongly on the relative velocity for a given value of the detection distance. Then, we investigate the effects of the speckles noise on the LDV for remote audio detection, and the results indicate that speckles noise can cause spikes and bursts appearing in the LDV-captured voice signals, which degrades the quality of the speech. To address this issue, an algorithm of the speckle noise reduction in the LDV-measured audio signals is proposed and the experimental results demonstrate that the proposed algorithm performs well.