Turbulence effect mitigation using adaptive optics post-processing of holographically recorded short-exposure images

摘要

We present a post-processing technique for mitigating the effect of turbulence on holographically recorded short-exposure images that consists of the two following sequential steps. First, the coherent field scattered from the viewed object propagates through a turbulence layer and is used to record a short-exposure Fourier hologram by interference with a know reference beam. Information about the instantaneous distorted optical field is hence stored permanently in the hologram. Secondly, the recorded hologram is read a posteriori using the reference beam with its wavefront modulated using adaptive optics. The resulting intensity image is used to compute a sharpness metric. Optimization of the metric is performed using a stochastic parallel gradient descent (SPGD) algorithm. Experimental and numerical results show an improvement of the image quality after convergence of the SPGD algorithm.