Method of filtering acoustic b-scan signals for passive detection of an object underwater

Abstract

A method of filtering an acoustic B-scan (500) for passive detection of an object (106, 108) underwater comprising ensonifying (400) a region (104) of an underwater environment (102) and receiving (402) acoustic signals from the ensonified region (104) of the underwater environment (102), the received acoustic signals corresponding to a plurality of sonar beams. The method also comprises generating (404) the acoustic B-scan (500) from the received acoustic signals and pre-processing (406-414) the acoustic B-scan (500) to remove historic artefacts and mitigate influence of reverberant energy. Energy content is then scored (416) in respect of the pre-processed acoustic B-scan (524) to provide a plurality of energy scores and at least one local maximum (200) of the plurality of energy scores is; identified (418). A predetermined criterion is then applied (808) to a local maximum (700) of the at least one local maximum (700) identified.

Dependencies are inferred from the claim text.