Abstract: A flexural pivot bearing includes a pair of members with opposed close-spaced faces which are joined by a web (29), of microscopic thickness, in a plane intersecting the faces. These members and the web are comprised of an integral body (27) of substantially uniform material, and the members are adapted for pivoted mutual flexure about a pivot axis aligned along the web.

Abstract: An array of acoustic sensors is positioned near the object to be imaged so that an array of detection beams impinge upon the surface of the object. The ambient noise in the ocean which is generated by both natural and manmade phenomena is reflected off of the target object and collected by the acoustic sensors. Each beam corresponds to a single pixel of an image of the object. The amplitude and frequency differences between the signals derived from each beam permit contrast to be developed between the pixels so that an image is formed. A first embodiment utilizes a parabolic or spherical reflector to focus the noise reflected from the object onto one or more sensors. A two dimensional array of sensors is required to produce an image. A second embodiment uses a phased array of acoustic sensors to form an image, with the phased array of sensors being used to generate a large number of scanned beams, each beam corresponding to one pixel of the image.