We discuss an efficient phase preserving technique for ScanSAR focusing, used to obtain images suitable for ScanSAR interferometry. Given two complex focused ScanSAR images of the same area, an interferogram can be generated as for conventional repeat pass SAR interferometry. However, due to the nonstationary azimuth spectrum of ScanSAR images, the coherence of the interferometric pair and the ...

D G Corr , S R Cloude , L Ferro-Famil , D H Hoekman , K Partington , E Pottier (3) and A Rodrigues (7) (1) QinetiQ Ltd, Room 1004, A8 Building,, Cody Technology Park, Farnborough, Hants. GU14 0LX, UK Email:[email protected] (2) AELc, Granary Business Centre, Unit 3.3, Fife. KY15 5YQ, UK Email: [email protected] (3) IETR, Université de Rennes I, Bât 11D, 263 Avenue Général Leclerc, CS 742...

The dark-speckle method (Labeyrie 1995) combines features of speckle interferometry and adaptive optics to provide images of faint circumstellar material. We present preliminary results of observations, and simulations concluding to the feasibility of exo-planet imaging from the ground. Laboratory simulations with an avalanche photodiode indicate the detectability of a stellar companion of rela...

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With its nearly 40 years of existence, speckle interferometry (SI) has become a complete technique, widely used in many branches of experimental mechanics. It is thus a challenging task to try to summarise in a couple of pages its principal characteristics from both theoretical and practical points of view. Admittedly, even though this goal is not met here, it appeared worth attempting to provi...

Interferometry is discussed in terms of the representation of the source. In particular, scale– invariant 1–d hydrodynamics is revisited, and extended to the case of unequal transverse masses. It is argued that that kaon emission occurs over a short time interval. Exact results for models of two– and three–dimensional flow are presented, which exhibit altered scaling laws. Such qualitative tren...

Stellar nulling interferometry offers the possibility of direct imaging of extrasolar planets necessary for the detection of extra-terrestrial life. Achieving optimum performance from the interferometers requires that the wavefronts of light reaching the interferometer are free of distortions. This is achieved by using single-mode fibers, which are excellent wavefront filters. In this paper, we...

Moire interferometry is employed to study toughening in medium to large grain size nominally pure alumina. The fracture scale length, which is characterized by the grain size of the alumina, is systematically varied from 35 to 102 p,m. R curves are derived from bulk mode I compliance calculations for the differing grain sizes and from the near tip moire fringes. The level of material toughening...

We describe a four-frame picosecond green laser interferometer developed at the Neptune Laboratory at UCLA. This diagnostic is applied for measuring the dynamics of CO2 laser produced plasmas in a He gas jet. An example of results of the modification of the plasma density profile by the radiation pressure of the laser pulse is presented.

The white dwarf Giclas 29-38 has attracted much attention due to its large infrared excess and the suggestion that excess might be due to a companion brown dwarf. We observed this object using speckle interferometry at the Keck telescope, obtaining diffraction-limited resolution (55 milliarcseconds) at K band, and found it unresolved. Assuming the entire K band excess is due to a single point-l...