An Electronically Focused Acoustic Imaging Device

Abstract

We describe in this paper a new technique for processing acoustic information from a piezoelectric array. The device we shall describe is capable of presenting dynamic, nearly real time images of acoustic objects whether they be internal body organs in medical applications, wreakage in the sea, or flaws in nondestructive testing. The present device is capable of 1 mm resolution at distances of 20 cm and operates without the use of an external focusing element or an intermediary hologram. In the experimental results reported here two dimensional images are obtained using electronic scanning in one dimension and mechanical scanning in the other dimension. We will describe near the end of this paper how a fully electronic two dimensional scan may be implemented. The sensitivity of the imaging apparatus is expected to be sufficient to insure low sound power levels while still obtaining high quality images.