Patent US 4,159,462

A steered beam B-scan ultrasonic imaging system has a linear transducer array divisible into multiple sub-arrays of transducer elements each operable to perform a sector scan, with the origin points displaced longitudinally along the array between sector scans. The system performs overlapping sector scans and is capable of imaging randomly oriented specularly reflecting targets. Time delays in the transmitting and receiving channels to steer the transmitted beam and to focus the received echoes are provided by digital techniques, by reversible digital shift registers, or by charge coupled device delay lines. The multiple sector image is displayed in real time in an intensity versus displacement format on a cathode ray tube.