Abstract: Satellite imaging through a turbulent atmosphere is provided at better than turbulence-limited resolution using laser speckle statistics on reflections of orthogonal spatially periodic illumination patterns. The second harmonic of a covariance function of phase provides the phase difference between nearby spatial frequencies. By summing such phase differences over many spatial frequencies a spectral phase distribution of an image can be obtained. A spectral intensity distribution can be obtained using laser speckle statistic during uniform illumination of the target. The combined intensity and phase spectral distributions can be inverse Fourier transformed to obtain the desired image.

Abstract: Changes in an image are detectable by a tracking novelty filter while an incorporated holographic medium is in disequilibrium. A suitably doped single-domain barium titanate crystal can serve as the holographic medium. Image information is imposed on a laser beam in the form of a spatially varying polarization across the beam cross section spatial position. The modulated beam is directed to the crystal, which cooperates with a polarizing beam splitter and a half wave plate to define a polarization conjugator. The conjugated beam is passed through the modulator a second time and then operated on by a beam splitter. When the crystal is in equilibrium with the incident laser light, the beam splitter directs minimal light to a detector. However, when an image change causes a change in the applied modulation, the changed image elements are intensified at the detector while the holographic medium is in disequilibrium. In alternative embodiments, phase is the variable modulated.