Study on Pulse Compression Ultrasonic Imaging by a Stacked M‐Sequence Encoding Probe

Abstract

If an ultrasonic imaging inside an object is possible without scanning by using an ultrasonic probe having a small aperture, the ultrasonic imaging system becomes a simpler and easier system. We have developed a stacked encoding ultrasonic transducer which can transceive an M-sequence signal only by a pulse drive in order to realize an ultrasonic measurement with a high resolution and high sensitivity. When an ultrasonic probe with such transducer is used, a pulse compression measurement is enabled only with a general ultrasonic flaw detector and a personal computer (PC) without using special devices. In this study, we focused on the characteristic that the received waveform by this probe changes with transceiver directions of a wave. A stacked M-sequence encoding probe of 7 bits length was manufactured and the one-dimensional point spread function in transceiver angle was obtained. As a result, it was confirmed that this probe has not only the pulse compression characteristic, but also the angle selecting characteristic. Finally, by using the proposed probe, the crosssectional imaging for point objects without scanning was demonstrated. C⃝ 2018 Wiley Periodicals, Inc. Electr Eng Jpn, 207(1): 36-42, 2019; Published online in Wiley Online Library (wileyonlinelibrary.com).