On the resolution characterization of THz and MMW FPA-based active imaging systems

Abstract

For numerous years, INO has been developing active video rate THz imaging systems operating in the 250-750 GHz band. These systems are designed for use in application fields such as security and industrial inspection. Although such systems are already deployed in the field, standard procedures for determining key metrics of their performances such as resolution and SNR are still work in progress. To support and validate the ongoing development of our systems, proper characterization methods are needed. This article describes our development on the use of various resolution targets and measurement procedures for characterizing our FPA-based THz active imaging system prototypes operated in reflection mode (collecting energy reflected by the observed scene). We analyze and discuss the results obtained with different resolution targets such as bar charts, Siemens chart, slanted edge and point sources. The repeatability and applicability of the methods are assessed by repeating the measurement procedure and analyzing the measurement discrepancies. Our results are compared to theoretical expectations when available.