Use of acoustic classification of sidescan sonar data for mapping benthic habitat in the Northern Channel Islands, California

2002 ◽  
Vol 22 (5) ◽  
pp. 683-690 ◽  
Author(s):  
Guy R. Cochrane ◽  
Kevin D. Lafferty
2010 ◽  
Vol 67 (8) ◽  
pp. 1766-1779 ◽  
Author(s):  
Alexandre C. G. Schimel ◽  
Terry R. Healy ◽  
David Johnson ◽  
Dirk Immenga

Abstract Schimel, A. C. G., Healy, T. R., Johnson, D., and Immenga, D. 2010. Quantitative experimental comparison of single-beam, sidescan, and multibeam benthic habitat maps. – ICES Journal of Marine Science, 67: 1766–1779. Map comparison is a relatively uncommon practice in acoustic seabed classification to date, contrary to the field of land remote sensing, where it has been developed extensively over recent decades. The aim here is to illustrate the benefits of map comparison in the underwater realm with a case study of three maps independently describing the seabed habitats of the Te Matuku Marine Reserve (Hauraki Gulf, New Zealand). The maps are obtained from a QTC View classification of a single-beam echosounder (SBES) dataset, manual segmentation of a sidescan sonar (SSS) mosaic, and automatic classification of a backscatter dataset from a multibeam echosounder (MBES). The maps are compared using pixel-to-pixel similarity measures derived from the literature in land remote sensing. All measures agree in presenting the MBES and SSS maps as the most similar, and the SBES and SSS maps as the least similar. The results are discussed with reference to the potential of MBES backscatter as an alternative to SSS mosaic for imagery segmentation and to the potential of joint SBES–SSS survey for improved habitat mapping. Other applications of map-similarity measures in acoustic classification of the seabed are suggested.


Phonetica ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Qandeel Hussain ◽  
Alexei Kochetov

Abstract Punjabi is an Indo-Aryan language which contrasts a rich set of coronal stops at dental and retroflex places of articulation across three laryngeal configurations. Moreover, all these stops occur contrastively in various positions (word-initially, -medially, and -finally). The goal of this study is to investigate how various coronal place and laryngeal contrasts are distinguished acoustically both within and across word positions. A number of temporal and spectral correlates were examined in data from 13 speakers of Eastern Punjabi: Voice Onset Time, release and closure durations, fundamental frequency, F1-F3 formants, spectral center of gravity and standard deviation, H1*-H2*, and cepstral peak prominence. The findings indicated that higher formants and spectral measures were most important for the classification of place contrasts across word positions, whereas laryngeal contrasts were reliably distinguished by durational and voice quality measures. Word-medially and -finally, F2 and F3 of the preceding vowels played a key role in distinguishing the dental and retroflex stops, while spectral noise measures were more important word-initially. The findings of this study contribute to a better understanding of factors involved in the maintenance of typologically rare and phonetically complex sets of place and laryngeal contrasts in the coronal stops of Indo-Aryan languages.


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