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In this paper, a new approach of images coding by Shapiro algorithm (embedded zerotree wavelet algorithm or EZW) is proposed. This approach, the modified EZW (MEZW), distributes entropy differently than Shapiro's and also optimizes the coding. This can produce results that are a significant improvement on the PSNR and compression ratio obtained by Shapiro,(More)
Terrestrial planet finder (TPF) is a space telescope mission which performs spectral analysis of the infrared emissions from extrasolar planets, and which searches for carbon-based life on such planets. One configuration being considered for this mission is a stellar interferometer with several collectors and a combiner on separate spacecraft flying in a(More)
The objective of the Terrestrial Planet Finder (TPF) mission is to find and characterize earth-like planets orbiting other stars. Three architectural options are under consideration for this mission: a formation-flying interferometer (FFI), a structurally-connected interferometer, and a coronagraph. One of these options can be selected as the TPF baseline(More)
Main brassboard Michelson interferometer components have been recently developed for the future flight phase implementations of SIM Lite mission. These brassboard components include two fine steering mirrors, pathlength modulation and cyclic averaging optics and astrometric beam combiner assembly. Field-independent performance tests will be performed in a(More)
The formation control testbed (FCT) is a ground based multiple robot testbed for simulating the dynamic interaction of spacecraft formations in a representative 6-DOF environment. Linear and spherical air bearings are used to mimic the drag free space environment. Each robot is fully autonomous with a self contained supply of float gas, integrated battery(More)
In this paper, we consider the problem of radar detection using the Gabor transform in presence of unknownpsilas noise and clutter. We proposed a new constant false alarm rate (CFAR) detector in time frequency domain to locate the positions of the targets exactly. This method is efficient in measurement as the case of no homogeneity is dealt with thus the(More)
The SIM Lite Astrometric Observatory is to perform narrow angle astrometry to search for Earth-like planets, and global astrometry for a broad astrophysics program, for example, mapping the distribution of dark matter in the Galaxy. The new SIM Lite consists of two Michelson interferometers and one star tracking telescope. The main six-meter baseline(More)
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