2016 Volume 36 Issue 4 Pages 398-406
This technical report describes a demonstration experiment for estimating water depth in shallow sea areas using Hodoyoshi-1 multispectral (MS) sensor. Hidoyoshi-1 is the first microsatellite funded by the Japanese Office of Cabinet and Japan Society for the Promotion of Science as part of the FIRST (Funding Program for World-Leading Innovative R&D on Science and Technology) program. Hodoyoshi-1 was developed based on “Reasonably Reliable Systems Engineering” concept. The microsatellite was launched on 6th November, 2014. Hodoyoshi-1 carries an optical MS sensor which provides blue (450 to 520nm), green (520 to 600nm), red (630 to 690nm) and near infrared (780 to 890nm) bands at 6.7 meter spatial resolution. Hodoyoshi-1 is a low-cost satellite imagery product that is expected to boost the remote sensing industry. In this report, Hodoyoshi-1 acquired imagery of several shallow sea areas, which were published on large-scale NOAA nautical charts. A linear algorithm (LA) - which has been successfully used for water depth estimation - achieved high estimation accuracy (determination coefficient is 0.819) using Hodoyoshi-1 MS imagery. The support vector machine (SVM) regression, a well-known robust estimation model, achieved equivalent estimation accuracy (determination coefficient is 0.891). Furthermore, comparison of estimated water depth maps and root mean square error in each depth indicate that SVM is capable of wide and deep coverage. Hidoyoshi-1 MS sensor performed relatively well for extracting the earth surface information as well as estimating water depth based on SVM. However, Hodoyoshi-1 imagery does not have Rational Polynomial Coefficients (RPC). In addition, the imagery has low location accuracy without ground control points (GCPs). As a result, Hodoyoshi-1 failed to produce an estimation model in a complex seafloor topography area. This issue would be resolved by improving location accuracy and performing geometric correction method for Hodoyoshi-1.
