Audio signal reconstruction based on adaptively selected seed points from laser speckle images

Speckle patterns, present in the laser reflection from an object, reflect the micro-structure of the object where the laser is illuminated on. When the object surface vibrates, the speckle patterns move accordingly, and this movement can be recovered with a high-speed camera system. Due to the low signal to noise ratio (SNR), it is a challenging task to recover the micro-vibration information and reconstruct the audio signal from the captured speckle image sequences fast and effectively. In this paper, we propose a novel method based on pixels׳ gray value variations in laser speckle patterns to work out with the challenging task. The major contribution of the proposed method relies on using the intensity variations of the adaptively selected seed points to recover the vibration information and the audio signal with a novel model that effectively fuses the multiple seed points׳ information together. Experiments show that our method not only recovers the vibration information with high quality but is also robust and runs fast. The SNR of the experimental results reach about 20 dB and 10 dB at the detection distances of 10 m and 50 m, respectively.