EXTRACTION OF INTERNAL SPATIAL FEATURES OF INHOMOGENEOUS DIELECTRIC OBJECTS USING NEAR-FIELD REFLECTION DATA

Ultra-wideband (UWB) microwave radar imaging tech- niques provide a non-invasive means to extract information related to an object's internal structure. For these applications, a short-duration electromagnetic wave is transmitted into an object of interest and the backscattered flelds that arise due to dielectric contrasts at interfaces are measured. In this paper, we present a method that may be used to estimate the time-of-arrival (TOA) parameter associated with each re∞ection that arises due to a dielectric property discontinuity (or di- electric interface). A second method uses this information to identify the locations of points on these interfaces. When data are collected at a number of sensor locations surrounding the object, the collection of points may be used to estimate the shape of contours that segre- gate and enclose dissimilar regions within the object. The algorithm is tested with data generated when a cylindrical wave is applied to a num- ber of numerical 2D models of increasing complexity. Moreover, the algorithm's feasibility is evaluated using data generated from breast models constructed from magnetic resonance (MR) breast scans. Re- sults show that this is a promising approach to identifying regions and the internal structure within the breast.