caa a22 4500 397550863 CHVBK 20180308164749.0 cr unu---uuuuu 161202e199604 xx s 000 0 eng 10.1006/jmsc.1996.0046 doi (NATIONALLICENCE)oxford-10.1006/jmsc.1996.0046 A post-processing technique to remove background noise from echo integration data [Elektronische Daten] [Jonathan L. Watkins, Andrew S. Brierley] Echo integration of biological organisms with a low target strength can be difficult because of the problem of setting suitable pre-integration thresholds, and this is particularly acute with higher frequencies, such as 120 or 200 kHz, which are often used in studies of euphausiids. One solution is to integrate data without any threshold and then remove background noise during post-processing. Unthresholded, integrated data of micronekton and Euphausia superba collected with a SIMRAD EK500 at frequencies of 38 and 120 kHz are presented. The underlying background noise level follows a 20 log R+2αR relationship, which can be scaled to the minimum volume backscatter (Sv) in each layer during a transect and then subtracted from the entire data set to remove background noise. The utility of this procedure is demonstrated by making comparisons of Sv at each frequency and investigating the effect of noise removal on the identification of targets based on the dB difference (120 kHz Sv-38 kHz Sv). © 1996 International Council for the Exploration of the Sea Regular Articles nationallicence echo integration nationallicence noise removal nationallicence threshold nationallicence Watkins Jonathan L. British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, England aut Brierley Andrew S. British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, England aut ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 339-344 1054-3139 53:2<339 1996 53 icesjms https://doi.org/10.1006/jmsc.1996.0046 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1006/jmsc.1996.0046 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Watkins Jonathan L. British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, England aut NATIONALLICENCE 700 1- Brierley Andrew S. British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, England aut NATIONALLICENCE 773 0- ICES Journal of Marine Science Oxford University Press 53/2(1996-04), 339-344 1054-3139 53:2<339 1996 53 icesjms Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford