Experimental validation of extended image reconstruction using bispectral speckle interferometry.

摘要

Results will be presented from a horizontal path imaging experiment in which we used a 0.5 meter telescope focused on a target located at a range of 1.2 km. The targets included various extended objects from a simple binary letters to extended representations of satellites with grey scale and size variations. Imaging at a center wavelength of 0.7 microns, we found an atmospheric degradation factor of D/r(sub o) = 17, on average. We used a slow read-rate bare CCD detector and thus had to effectively deal with additive noise in the speckle measurements. Our image reconstruction algorithms are based on the use of the complex bispectrum and we have demonstrated diffraction-limited imaging down to light levels approaching a few photons per speckle resolution area. We have paid careful attention to the effects of additive noise on the reconstruction process and shown that they can be adequately overcome. 11 refs., 8 figs.