In this paper, the design and implementation of a sub-millimeter line scanning imager using a novel imageforming device is described. The system consists of a coherent illuminator, an optical system, an image plane mask, and a coherent detector. The image plane mask is formed by making a sequence of holes along a constant radius of a metal disk. Spinning the disk scans the holes through the image formed on it. A detector placed behind the spinning disk collects radiation passing through the holes. The holes are arranged in a pseudorandom pattern. At each detector sample time, energy from a different pattern of holes is collected. A rigorous electromagnetic analysis shows that, for a certain minimum size and spacing of holes and certain disk thicknesses, these measurements constitute a linear measurement of the energy in the image formed on the disk. Using techniques reminiscent of those used in compressive sensing, the image is then reconstructed by applying an inverse linear matrix transform to these measurements. We show how simulation can be used to optimize the design of the disk. We demonstrate a laboratory version of this device and discuss future efforts to systematize it. Extensions to full two-dimensional imaging are also discussed.

Date Published: 12 October 2010
PDF: 11 pages
Proc. SPIE 7837, Millimetre Wave and Terahertz Sensors and Technology III, 78370D (12 October 2010); doi: 10.1117/12.865100

Published in SPIE Proceedings Vol. 7837:
Millimetre Wave and Terahertz Sensors and Technology III
Keith A. Krapels; Neil A. Salmon, Editor(s)