INTERFEROMETRIC IMAGE ACQUISITION AND RECONSTRUCTION

摘要

To obtain an image of an exo-solar planet, a space-borne interferometric imaging system consisting of free-flying spacecraft (telescopes) is considered. A brief account of the underlying mathematics of image synthesis via interferometry is reviewed. A measure of image quality is adopted based on the estimated image and the Modulation Transfer Function (MTF) of the entire formation. The coordination of the formation is required to execute optimal formational maneuvers that correlate to a coverage problem; in which the resolution disc in the spatial frequency plane must be entirely covered via coverage discs that represent the mutual light measurements from pairs of telescopes. We formulate and find the necessary conditions of optimality for the coverage task via the coordinated maneuvers of the spacecraft formation. Minimum time bounds for achieving complete coverage are found. Finally, given the relative position data of the formation and using the measure of image quality to redirect the spacecraft maneuvers, we address the problem of accounting for the regions that are not completely covered in the resolution disc. We show the feasibility of using signal processing techniques to account for these regions of attenuation rather than have the formation reposition itself in order to achieve complete coverage.