A noise removal algorithm for acoustic data with strong interference based on post-processing techniques

The use of fishing-vessel-based acoustic data has been recognized by SC-CAMLR as an important way to estimate the distribution and relative abundance of Antarctic krill (Euphausia superba), yet the quality and even the utility of the data may be seriously degraded by interferences due to the lack of synchronization device for the acoustic instruments equipped on some of the vessels. A simple algorithm to remove noise and significant interference from other acoustic instruments was introduced. The algorithm was built on relevant modules in the Echoview acoustic data post-processing software. The utility of the method was demonstrated by comparing the appearances of krill swarm echograms, the dB differences and the echo integrations. Results showed that the interference were effectively removed while the retained krill swarms were maintained in good geometrical shape and volume backscatter strength.