Side scan sonar data quantification for seabed classification in Yos Sudarso Bay, Jayapura

Abstract

Side Scan Sonar (SSS) is an instrument that is usually used in surveys to perform seabed imaging. SSS was able to show two-dimensional images of the seabed with contour, topographic, and target conditions simultaneously. This technology is capable of distinguishing seabed types such as rocks, sand, or others. In addition, the usefulness of this technology can also detect the existence of marine pipes and cables, shallow structures of the seabed, dredges, environmental studies, military, archaeology, fisheries, and mining. The aims of this research were to identify and interpret the seabed, measure the acoustic backscatter (dB) and amplitude (mV) of the seabed substrate, and compute SSS data using Continuous Wavelet Transform (CWT) in the Yos Sudarso Bay, Jayapura. Processing data was performed by radiometric Beam Angle Correction (BAC), Automatic Gain Control (AGC), and geometric (bottom tracking) corrections using SonarWiz 7 software. Pre-processed SSS data were then converted to XtfToSegy and the amplitude values were exported by SeiSee software, and CWT was calculated using Matlab. Amplitude data was visualized using Microsoft Excel to display a relation between amplitude, time, and CWT graph. The results of seabed detection were three areas of sand and one coral target. The amplitude value of sand 1 ranged from 4319 to 30976 mV with the = backscatter value was -17.10 dB. The amplitude value of sand 2 ranged from 1411 to 12288 mV with the backscatter value was -18.79 dB. The amplitude value of sand 3 ranged from 1391.625 to 12032 mV with the backscatter value was -18.70 dB. The amplitude of the coral ranged from 24960 to 32640 mV with the backscatter value was -2.30 dB. The CWT analysis results show that the yellow-coloured coral’s energy represents a rougher and harder object. The energy generated from the blue-coloured sand represents the object has smooth and non-hardening characteristics.