SEABED CLASSIFICATION BY QTC VIEW - SITES NEAR VANCOUVER ISLAND

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Authors
  1. Tsemahman, A.S.
  2. Collins, W.T.
Corporate Authors
Defence Research Establishment Atlantic, Dartmouth NS (CAN);Quester Tangent Corp, Sidney BC (CAN)
Abstract
The aim of this study was to determine QTC VIEW's ability to classify typical seabed types encountered in harbours near the southeastern shore of Vancouver Island and adjacent Gulf islands. Twenty-two calibration sites were chosen and geotechnical data collected for each. During the March 1996 trial on CSS Vector, echo sounder pings were recorded as the ship followed transits over the calibration sites. The approach to seabed classification described in this report is based on extraction of characteristic features from an acoustic echo. The echo shape is determined mainly by the sea bottom roughness and by the contrast in acoustic impedance between water and bottom. Several statistical and spectral algorithms were used to generate a full feature vector from the preprocessed individual echoes. Principal component analysis of the full feature vectors yielded a small number of indices which accounted for most of the variation in the original data set. Over a survey area, indices were clustered and, using software found four acoustically distinct classes. The geotechnical analysis showed three broadly classified groups: relatively coarse sediments (mostly sand), fine sediments (generally silt), and fine sediments with a high degree of consolidation. A catalogue of classes built upon the results of calibration was then used to classify several transits in the studied area. TRUNCATED
Keywords
C-VIEW;Seabed classification
Report Number
DREA-CR-96-462 — Contractor Report
Date of publication
01 Oct 1996
Number of Pages
60
DSTKIM No
98-00410
CANDIS No
506998
Format(s):
Hardcopy;Document Image stored on Optical Disk

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