Abstract: A method and apparatus for producing a linear plan view display of a seabed, employing a side scan sonar signal system, have circuitry for repeatedly determining the height of the transmitting source relative to the seabed, circuitry for sampling the returning sonar signals, and circuitry for providing from the height determination and the sampled signals, the slant range correction needed to provide a linear output display, at least in a direction normal to the direction of movement of the transmitting source. The preferred method and apparatus also have elements for determining the velocity of the transmitting source and for effecting a one-to-one aspect ratio linear plan view of the seabed topography. In other aspects of the invention, a method and apparatus for controlling the display and for implementing the mapping transformation are described.

Abstract: A bulb-shaped flashtube is provided with a metal envelope to increase its strength and enhance its reliability and operating characteristics. The metal envelope comprises a hollow cylindrical container including an open bottom end and an inwardly extending annular flange at its top end which defines a window opening in the container. A circular base of insulating material is sealed in the open bottom end of the container. A plurality of conductors extend through the insulating base to support a plurality of electrodes within the container. A circular, transparent window is sealed to the annular flange inside the top end of the container for transmitting a flash of light upon electrical discharge between the electrodes.

Abstract: Lines on an image are optically scanned in sequence for image density at spaced intervals. Binary line scan functions are produced to represent the densities of the samples. These functions are translated into equivalent binary line codes of substantially reduced redundancy and length. Translation is accomplished by generating codes defining the variations of each line scan function from that of the previous line.

Abstract: An improved rotating bellows seal is disclosed which includes a bellows core having an annular mounting plate at one end adapted to drivingly and sealingly engage a shaft and a bellows seal ring on the other end to sealingly engage a mating seal ring. The mating and bellows seal rings are provided with conical inside diametral surfaces to prevent leakage fluids from entering the bellows core.