High resolution holographic imaging with a robot scanner and its applications

The high spatial resolution offered by the holographic radar operating in the frequency range 2GHz–8GHz can be fully exploited in field surveys if the radar head can scan large areas with spatial resolution and accuracy corresponding to a fraction of the wavelength. For the typical operating frequencies this requires a millimeter resolution of the acquisition system. For achieving these requirements a robot scanner is proposed and the realization of the main blocks is described. The advantage of this approach for fast and accurate subsurface imaging is demonstrated with laboratory experiments for the detection of defects on the bonding of thermal insulating material on a metal sheet. For more complex environments like natural soil a multisensory system is proposed and a low cost range meter with special design of the ultrasonic transducers is proposed. The profile of the surface is an important information for obtaining the best resolution of buried object underneath irregular surfaces.