CONFOCAL ULTRASONIC IMAGING SYSTEM

An ultrasonic imaging system incorporates an imaging device utilizing confocal acoustic focusing of ultrasonic transducers together with apparatus for moving points of focus of the transducers to scan a volume to be imaged and gather data as to the acoustic reflectivity of matter within the volume, the gathered data being used to construct an image of the volume. In a preferred arrangement the point of focus of each transducer is moved in three dimensions. Use of confocal techniques can permit enhanced resolution to be obtained compared with conventional ultrasonic imaging techniques. In a preferred arrangement, the confocal focusing system associated with each transducer includes a pinhole which is bridged by an acoustically transparent but optically reflective diaphragm, and acoustic reflectivity data is recovered by interrogating each diaphragm by means of an optical interferometer. Optical signals from the interferometer may be scanned over an array of optical sensors such as a charge coupled device array to segment and temporarily store the optical data.