Ray Tracing Model for Terahertz Inspection of Spray On Foam Insulation (SOFI)

Abstract

Terahertz imaging techniques are beginning to find many applications in areas such as nondestructive evaluation, biomedical imaging and homeland security. The NASA spray on foam insulation (SOFI) inspection is a critical application where terahertz imaging is used to detect disbonds and delamination between SOFI and the substrate metal (external tank). This paper discusses a ray-tracing model for the high frequency inspection system. Model based inversion techniques for the characterization of defects is also proposed