A method and system for inspecting a structure. The method may comprise sending a pulsed wave signal into the structure from a transmitter array. The method may detect a response signal in response to sending the pulsed wave signal into the structure at a group of receivers in a receiver array. The method may identify a group of time delays between sending the pulsed wave signal and may detect the response signal generated in response to the pulsed wave signal at the group of receivers. The method may identify a group of intensities for the response signal detected at the group of receivers. The method may determine a distance to a reflector within the structure using the group of time delays and the group of intensities.