Iterative correction procedure for images degraded by turbulence

A recently introduced approach to restore images distorted by atmospheric turbulence without a direct knowledge about the wavefront is being discussed in this paper. This technique is based on the use of a deformable mirror controlled by a Stochastic Parallel Gradient Descent (SPGD) algorithm applied to an image quality measurement. This procedure is now being tested for the correction of extended sources as well as laser beams. Because the technique does not rely on wavefront sensors, the problems related to scintillations are noticeably reduced. Preliminary results are presented.