1. A system for characterizing a spot weld, comprising: (a) an acoustic probe, wherein the acoustic probe further includes: (i) a plurality of ultrasonic transducer elements arranged in a curved array at one end of the acoustic probe, wherein the transducer elements are operative to both generate ultrasonic signals and to receive reflections thereof; and (ii) a combination of materials for allowing the probe to conform to a contoured surface of the spot weld while enabling sound energy to be transferred directly into the spot weld under test conditions, (b) a phased array excitation unit in electrical communication with the array of transducer elements for ultrasonically exciting transducer elements, and (c) a controller in electrical communication with the phased array excitation unit for controlling the operation of the phased array unit, gathering and processing information from the ultrasonic transducers, and generating a two-dimensional, color coded image that characterizes the integrity of the spot weld.