Abstract: A sonar system is provided for identifying a foreign object includes a technique for providing a two dimensional array of pixels, each one of the pixels representing the intensity of a signal at a predetermined range position and a predetermined cross-range position from a reference position and quantizing the intensity of each one of the pixels into one of a plurality of levels. The technique further includes comparing a distribution of the levels of pixels over a range scan at a cross-range position with the distribution of levels of pixels over a range scan at a different cross-range position to identify the existence of a foreign object. With such an arrangement a sonar system is provided that can automatically detect the existence of a foreign object such as a mine.

Abstract: A sonar system is provided for mapping the bottom of a body of water to identify a submerged foreign object. A sequence of the sonar pulses is transmitted and directed toward the bottom. The mapping is formed from a sequence of echo returns. Each one of the echo returns is produced as a range scan in a range direction response to a corresponding one of the transmitted sonar pulses. The sonar system stores signals representative of the intensity of the echo returns in a two dimensional array of pixels. Each one of the pixels represents the intensity of the echo return at a predetermined range position from the system in the range direction and a predetermined cross-range position from a reference position of the system in the cross-range direction.