Automatic speckle cancellation techniques for multidither adaptive optics

Analytical and computer simulation results show that it is possible to restore speckle-degraded performance of multidither adaptive optics systems. Such systems are known to be vulnerable to interference caused by the motion of a speckle pattern across their receiver apertures. Analysis has shown that the primary effect of speckel is to amplitude-modulate the usual point-source intensity distribution reflected from a target glint. With large targets there is also an additive noise contribution from the intensity associated with reflections from the area surrounding the target glint. A method is described whereby the speckle interference is estimated and electronically canceled in order to restore the degraded adaptive performance.