Wide-band synthetic aperture radar (SAR) technique,
capable of producing three-dimensional (3D) volumetric images,
is a robust imaging tool for microwave and millimeter wave
imaging involving nondestructive evaluation (NDE) applications.
Conventionally, a relatively large number of measurement
samples are required to image even a small area. Thus, it may
take a relatively long time to perform the required scan and
obtain an image. There is a significant push in the
nondestructive testing community towards real-time imaging,
particularly when dealing with large and critical structures (i.e.,
aircraft, bridges, space vehicles, etc.). Here, a method involving
non-uniformly sampled wide-band reflection measurements data
is described that enables the production of complete SAR images
using only a fraction of the required measured data. The imaging
method is based on a fast 3D wide-band SAR algorithm that
produces 3D SAR images in real-time. Finally, a reconstruction
algorithm is used to post-process the data resulting in high
quality images with considerably lower background noise/clutter.
This paper presents the measurement methodology along with a
few experimentally obtained images.