Modeling and Processing of Terahertz Imaging in Space Shuttle External Tank Foam Inspection

Recently, terahertz ray (T‐ray) imaging emerged as one of the most promising techniques to inspect the space shuttle external tank foam insulation. This paper demonstrates the application of state‐of‐the‐art computer processing and modeling technologies to assist in further refinement of this new technology. The current protocol of T‐ray inspection and its limitations are first reviewed. New strategies of using signal processing and modeling are then proposed to improve on the flaw detection. Preliminary results are presented on a series of multi‐dimensional signal processing operations of T‐ray signals. The use of models and their comparisons with experimental data from foam samples are also included.