Small signal detection filter

Abstract

A sonar device including reception circuitry and processing circuitry is disclosed. The reception circuitry acquires sonar data from one or more targets in an underwater environment. The processing circuitry includes a target detector, a first noise filter, a second noise filter, and a selector. The target detector generates a binary mask that indicates presence or absence of target based on the sonar data. The first and second noise filters receive the sonar data, perform first and second noise filtering on the sonar data to reduce noise in the sonar data respectively, and output first and second filtered sonar data respectively. The first noise filtering is based on a first threshold. The second noise filtering is based on a second threshold different from the first threshold. The selector selects one of the first filtered sonar data and the second filtered sonar data as output based on the binary mask.