Location

La Jolla, CA

Start Date

1981 12:00 AM

Description

We report progress with the development of a real-time, 32 element, synthetic aperture acoustic imaging system. Construction and testing of the system hardware is now complete, enabling us to acquire raw acoustic data and focus and display it with a frame rate of 30 Hz . Performance of the system is currently being assessed. Images of wire targets indicate that the resolution is as predicted by simple theory. The main thrust of our current effort is two-fold: we aim to use the system to examine "real" defects with acoustic surface waves and longitudinal waves, but at the same time improved understanding is needed to interpret the images obtained from more complex object fields. To this end, we are developing both theoretical and computer models for objects such as point targets, plane specular reflectors, and cylindrical inclusions. The results obtained from these models can be compared directly with images generated by the real-time system. It is likely that these results are common to other synthetic aperture systems and to any high frequency inversion process. The effects of nonlinear processing are also examined.

Book Title

Proceedings of the ARPA/AFML Review of Progress in Quantitative NDE

Chapter

8. Ultrasonic Imaging and Microscope

Pages

194-202

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

A Real-Time Synthetic Aperture Digital Acoustic Imaging System

La Jolla, CA

We report progress with the development of a real-time, 32 element, synthetic aperture acoustic imaging system. Construction and testing of the system hardware is now complete, enabling us to acquire raw acoustic data and focus and display it with a frame rate of 30 Hz . Performance of the system is currently being assessed. Images of wire targets indicate that the resolution is as predicted by simple theory. The main thrust of our current effort is two-fold: we aim to use the system to examine "real" defects with acoustic surface waves and longitudinal waves, but at the same time improved understanding is needed to interpret the images obtained from more complex object fields. To this end, we are developing both theoretical and computer models for objects such as point targets, plane specular reflectors, and cylindrical inclusions. The results obtained from these models can be compared directly with images generated by the real-time system. It is likely that these results are common to other synthetic aperture systems and to any high frequency inversion process. The effects of nonlinear processing are also examined.