Hybrid non-invasive ultrasonic imaging system

Abstract

Certain ones of a total array of ultrasonic transducers constitute a small aperture and are so energized as to project acoustic energy onto predetermined parts of a scene. Reflections of the transmitted signals are received by certain ones of the array, are converted to electrical signals and are appropriately delayed to enable additive combination of the amplitude of the received signals emanating from the same points in the scene ('targets'). The phase (or time delay) as well as the amplitude information of the reflective signals are stored. Next, the same transmitting elements ('subarray') project acoustic energy upon the remaining parts of the scene in sequence and the reflected signals are similarly processed and stored. This continues until all the parts of the predetermined scene have been interrogated by insonification from that subarray and the reflected signals have been similarly processed. Then, at least one more set of transducers of the total array, which also constitute a small aperture, are caused to scan the same parts of the image in the same sequence thereby producing the same types of reflected signals which are processed similarly, and whose amplitude and phase information is similarly stored. The plurality of the stored signals from each subarray, which may be termed 'complex image' signals, are then vectorially added and further processed to derive a video signal which is used to produce a final display image.