Ultrasonic Imaging in Layered Objects by Decomposing Spatiotemporal Signals into a Plane Wave Spectrum

A phased array approach to ultrasonic imaging through a set of layers with unknown parameters is considered. The technique is based on decomposing a recorded signal into a spectrum of plane pulsed waves and compensating for their delays in the layers. It is shown that the approach can be used for imaging and measuring the speed of sound by processing the echo from a detached small reflector.