Enhancing speech intelligibility in optical microphone systems through physics-informed data augmentation

Laser doppler vibrometers (LDVs) facilitate noncontact speech acquisition; however, they are prone to material-dependent spectral distortions and speckle noise, which degrade intelligibility in noisy environments. This study proposes a data augmentation method that incorporates material-specific and impulse noises to simulate LDV-induced distortions. The proposed approach utilizes a gated convolutional neural network with HiFi-GAN to enhance speech intelligibility across various material and low signal-to-noise ratio (SNR) conditions, achieving a short-time objective intelligibility score of 0.76 at 0 dB SNR. These findings provide valuable insights into optimized augmentation and deep-learning techniques for enhancing LDV-based speech recordings in practical applications.