Abstract: A acoustical imaging scanning head includes a roller driven optical encoder. The encoder and its shaft are isolated in a non-magnetic housing. The encoder shaft and a roller driven drive shaft are provided with permanent magnets on facing steel discs on opposite sides of a relatively thin wall of a non-magnetic housing. The encoder is sealed in a chamber in such housing and is totally isolated from the surrounding environment, including the drive shaft. The position and arrangement of the magnets maintains the ability to rotate the encoder shaft to produce electrical pulses proportional to the encoder shaft rotation.

Abstract: A scanner head for ultrasonic testing of structures includes a carriage with rollers supporting the carriage for movement over a surface being tested in a selected direction. A transverse frame is supported by the carriage and extends in a second direction crossing the one direction. A transducer is supported by the frame for movement along the frame to preset operative offset positions. For pipes or boiler tubes, the frame is in the form of an arc bar having a T-slot in which a holder for the transducer rides. With the carriage moving axially of the tube or pipe along a reference line, the arc bar keeps the transducer perpendicular to the surface regardless of the offset position. The rollers drive a distance increment signal generator to pulse the transducer and drive the ultrasonic transceiver and display circuitry.

Abstract: An imaging system for non-destructively imaging the cross-section of a workpiece is taught. The image provided portrays the cross-section of the workpiece taken orthogonal to the surface of the workpiece along an operator selected course on the surface. The imaging system comprises: a scanner means for transmitting and receiving acoustical signals and for providing distance increment signals; a transmit and receive control means responsive to each distance increment signal for providing an acoustical drive signal and a column clock signal set. A sampling means is provided that is responsive to the column clock signal set for converting each the echo signal into a corresponding column series of digital values, each value characterizing the amplitude of the echo signal at time corresponding to a respective column clock signal within the echo interval. A storage means is provided for storing each column series of digital values as successive column arrays to form an image array of digital values.