Analysis of Image Formation with Thinned Random Arrays
Abstract
Very high resolution imaging systems, regardless of wavelength, require large apertures with a high resolution, low sidelobe level and high gain. These apertures are often considered to be technically and economically infeasible. We investigated the efficacy of using very sparse arrays of randomly placed small antenna elements in imaging systems. The properties of these arrays are established in antenna theory. What we have done is to make the first demonstration of their application in imaging systems. Computer simulation studies were made for coherent, partially coherent, and incoherent imaging. These were done using various conditions, including variable signal-to-noise ratio and phase aberration, but with monochromatic illumination. We showed that, for incoherent imaging, a large degree of thinning down to 6% of the number of full array elements (4096) produces image quality comparable to that produced by the full array. For broad-band polychromatic incoherent imaging, even larger degrees of thinning, down to 3% were similarly effective. The fractional degree of thinning allowable for incoherent imaging in principle is inversely proportional to the square root of the number of elements in the full array, which number is equivalent to the number of elements resolved in the full array.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1979
- Accession Number
- ADA072512
Entities
People
- Bernard H. Soffer
- David Y. Tseng
Organizations
- HRL Laboratories