Two-dimensional, real-time, sub-millimeter wave imaging using a spatially selective mask


In the absence of detector arrays, a single pixel coupled with a spatially selective mask has been shown to be a practical solution to imaging problems in the terahertz and sub-millimeter wave domains. In this paper we demonstrate real-time two-dimensional imager for sub-millimeter waves that is based on a spatially selective image plane mask. The imager consists of a heterodyne source and receiver pair, image forming optics, a spatially selective mask, data acquisition hardware, and image reconstruction software. The optics form an image onto the spatially selective mask and linear measurements of the image are made. The mask must be designed to ensure maximum transmission, measurement linearity, and measurement to measurement independence and our design parameters are presented. Once enough linearly independent measurements are made, the image is reconstructed by solving a system of linear equations that is generated from the mask patterns and the corresponding measurements. We show that for image sizes envisioned for many current applications, this image reconstruction technique is computationally efficient and can be implemented in real time. We present images collected using this system, discuss the results, and discuss other applications for some components of the imager. © 2011 SPIE.

Publication Title

Proceedings of SPIE - The International Society for Optical Engineering