Sonic cameras

Abstract

Westinghouse is developing two different types of sonic cameras for real time imaging in turbid water. A 2-MHz side-look sonic camera has been built for viewing the ocean bottom at angles from 35° to 55°. The plane of the bottom is mapped into an image plane behind the lens. Ninety-eight line transducers are used in the image plane to form 98 simultaneous beams. Range resolution is determined by time, as in a side-look sonar, and angular resolution is determined by the lens. A 25-cm lens obtains resolutions of 1.5 to 6 cm at ranges from 3 to 12 m. A circular-scan camera has been built to operate at 3 MHz. This camera maps a plane orthogonal to the direction of view into the image plane behind the sonic lens. The image is swept out by a row of 128 transducers rotating in the image plane. A 27-cm lens makes it possible to achieve resolutions of 1 to 3 cm at ranges from 3 to 9 m. Lens data applicable to both cameras is given and initial pictures taken with both types of cameras are shown. Subject Classification: [43]35.80; [43]30.80; [43]35.65.