Showing papers by "Paul F. McManamon published in 2011"

Multi-aperture coherent imaging

Abstract: Aperture synthesis offers the potential for high resolution images in a relatively compact system. We describe our multiaperture IMAGE testbed which uses coherent detection to measure the complex field in spatially separated apertures. We describe a post-detection optimization algorithm which is used to synthesize a composite image whose angular resolution exceeds that of a single aperture. We present experimental results in which we image extended targets at a simulated range using a compact range developed for this purpose.

Piston phase determination and its effect on multi-aperture image resolution recovery

Abstract: Multi-aperture coherent LADAR techniques can be applied to generate high resolution images. When setting up a system with multiple sub-apertures, misalignment of the sub-apertures causes the beams entering the sub-apertures to have mismatched optical path lengths, which will degrade the image resolution. Post-processing using image sharpening techniques to correct for piston phase, as well as other aberration corrections, require computing power and time. We study whether the processing time can be shortened by providing measured piston phase information to the image sharpening algorithms. Simulations are used to demonstrate the usefulness of piston phase measurements. Simulations are presented showing the benefits of piston phase measurements for two or more sub-apertures. The speed of convergence for the sharpening algorithm both with and without the piston phase measurements are compared for multiple sub-aperture imaging.

Digital Holography for High-resolution, Multi-aperture Laser Radar

Abstract: Active remote sensing challenges using multi-aperture imaging experiments are described. The image resolution is limited by the accuracy in phasing all sub-apertures together. Efforts to overcome technical hurdles in achieving high resolution imagery are reported.