Two-dimensional displacement estimation of one-dimensional laser speckle images for detection of acoustic vibration

Detection and recovery of audio signals using optical methods is an appealing topic. Observing the movement of secondary speckle patterns is a convenient method for such a purpose. In order to have less computational cost and faster processing, one-dimensional laser speckle images are captured by an imaging device, while it sacrifices the ability to detect speckle movement along one axis. This paper proposes a laser microphone system to estimate the two-dimensional displacement from one-dimensional laser speckle images. Hence, we can regenerate audio signals in real time even as the sound source is rotating. Experimental results show that our system is capable of reconstructing audio signals under complex conditions.